1,992 results on '"Barrett, B"'
Search Results
2. Effective operators for valence space calculations from the {\itshape ab initio} No-Core Shell Mode
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Li, Zhen, Smirnova, N. A., Shirokov, A. M., Shin, I. J., Barrett, B. R., Maris, P., and Vary, J. P.
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Nuclear Theory - Abstract
In recent years, remarkable progress has been achieved in developing novel non-perturbative techniques for constructing valence space shell model Hamiltonians from realistic internucleon interactions. One of these methods is based on the Okubo--Lee--Suzuki (OLS) unitary transformation applied to no-core shell model (NCSM) solutions. In the present work, we implement the corresponding approach to solve for valence space effective electromagnetic operators. To this end, we use the NCSM results for $A=16-18$, obtained at $N_{\rm max}=4$, to derive a charge-dependent version of the effective interaction for the $sd$ shell, which allows us to exactly reproduce selected NCSM spectra of $^{18}$O, $^{18}$F and $^{18}$Ne within the two valence nucleon space. We then deduce effective single-particle matrix elements of electric quadrupole ($E2$) and magnetic dipole ($M1$) operators by matching them to the electromagnetic transitions and moments for $^{17}$O and $^{17}$F from the NCSM at $N_{\rm max}=4$. Thus, effective $E2$ and $M1$ operators are obtained as sets of single-particle matrix elements for the valence space ($sd$ shell) which allow us to reproduce the NCSM results for $A=17$ exactly. Systematic comparison of a large set of $sd$ shell results on quadrupole and magnetic dipole moments and transitions for $A=18$ using effective $E2$ and $M1$ operators that we derive from the full NCSM calculations demonstrates a remarkable agreement., Comment: Submitted for publication in the Akito Arima Memorial Volume, World Scientific, T.T.S. Kuo, T. Otsuka and K.K. Phua, Editors
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- 2022
3. Carrier-Suppressed Multiple Single-Sideband Laser Source for Atom Cooling and Interferometry
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Templier, S., Hauden, J., Cheiney, P., Napolitano, F., Porte, H., Bouyer, P., Barrett, B., and Battelier, B.
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Physics - Atomic Physics ,Physics - Optics - Abstract
We present a new electro-optic modulation technique that enables a single laser diode to realize a cold-atom source and a quantum inertial sensor based on matter-wave interferometry. Using carrier-suppressed dual single-sideband modulation, an IQ modulator generates two optical sidebands from separate radio-frequency (rf) signals. These sidebands are controlled independently in frequency, phase, and power using standard rf components. Our laser source exhibits improved rejection of parasitic sidebands compared to those based on phase modulators, which generate large systematic shifts in atom interferometers. We measure the influence of residual laser lines on an atom-interferometric gravimeter and show agreement with a theoretical model. We estimate a reduction of the systematic shift by two orders of magnitude compared to previous architectures, and reach a long-term sensitivity of 15 ng on the gravitational acceleration with an interrogation time of only T = 20 ms. Finally, we characterize the performance of our integrated laser system, and show that it is suitable for mobile sensing applications including gravity surveys and inertial navigation., Comment: 14 pages, 11 figures
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- 2021
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4. Determination of a Safe Zone for Ischial Screw Placement in Total Hip Arthroplasty
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Bellas, Nicholas J., Baltrusaitis, David, Torre, Barrett B., Baldino, Joshua B., Sedghi, Tannaz I., Marrero, Daniel E., and Solovyova, Olga
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- 2024
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5. Early Tibial Baseplate Fracture After Medial Unicondylar Knee Arthroplasty: A Report of 2 Cases
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Torre, Barrett B., Pavano, Colin, Connors, John Patrick, Silver, Jacob, Bellas, Nicholas, Shekhman, Mark, and Solovyova, Olga
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- 2023
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6. Separated Kaon Electroproduction Cross Section and the Kaon Form Factor from 6 GeV JLab Data
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Carmignotto, M., Ali, S., Aniol, K., Arrington, J., Barrett, B., Beise, E. J., Blok, H. P., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Christy, M. E., Dittmann, A., Ent, R., Fenker, H., Gaskell, D., Gibson, E., Holt, R. J., Horn, T., Huber, G. M., Jin, S., Jones, M. K., Keppel, C. E., Kim, W., King, P. M., Kovaltchouk, V., Liu, J., Lolos, G. J., Mack, D. J., Margaziotis, D. J., Markowitz, P., Matsumura, A., Meekins, D., Miyoshi, T., Mkrtchyan, H., Niculescu, G., Niculescu, I., Okayasu, Y., Pegg, I., Pentchev, L., Perdrisat, C., Potterveld, D., Punjabi, V., Reimer, P. E., Reinhold, J., Roche, J., Sarty, A., Smith, G. R., Tadevosyan, V., Tang, L. G., Trotta, R., Tvaskis, V., Vargas, A., Vidakovic, S., Volmer, J., Vulcan, W., Warren, G., Wood, S. A., Xu, C., and Zheng, X.
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Nuclear Experiment - Abstract
The $^{1}H$($e,e^\prime K^+$)$\Lambda$ reaction was studied as a function of the Mandelstam variable $-t$ using data from the E01-004 (FPI-2) and E93-018 experiments that were carried out in Hall C at the 6 GeV Jefferson Lab. The cross section was fully separated into longitudinal and transverse components, and two interference terms at four-momentum transfers $Q^2$ of 1.00, 1.36 and 2.07 GeV$^2$. The kaon form factor was extracted from the longitudinal cross section using the Regge model by Vanderhaeghen, Guidal, and Laget. The results establish the method, previously used successfully for pion analyses, for extracting the kaon form factor. Data from 12 GeV Jefferson Lab experiments are expected to have sufficient precision to distinguish between theoretical predictions, for example recent perturbative QCD calculations with modern parton distribution amplitudes. The leading-twist behavior for light mesons is predicted to set in for values of $Q^2$ between 5-10 GeV$^2$, which makes data in the few GeV regime particularly interesting. The $Q^2$ dependence at fixed $x$ and $-t$ of the longitudinal cross section we extracted seems consistent with the QCD factorization prediction within the experimental uncertainty.
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- 2018
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7. Bilateral Flexor Digitorum Accessorius Longus Precipitating Bilateral Tarsal Tunnel Syndrome: A Case Report
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Propp, Bennett E., Torre, Barrett B., Bellas, Nicholas, and Sathe, Vinayak
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- 2023
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8. Generation of high-purity, low-temperature samples of $^{39}$K for applications in metrology
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Antoni-Micollier, L., Barrett, B., Chichet, L., Condon, G., Battelier, B., Landragin, A., and Bouyer, P.
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Physics - Atomic Physics ,Quantum Physics - Abstract
We present an all optical technique to prepare a sample of $^{39}$K in a magnetically-insensitive state with 95\% purity while maintaining a temperature of 6 $\mu$K. This versatile preparation scheme is particularly well suited to performing matter-wave interferometry with species exhibiting closely-separated hyperfine levels, such as the isotopes of lithium and potassium, and opens new possibilities for metrology with these atoms. We demonstrate the feasibility of such measurements by realizing an atomic gravimeter and a Ramsey-type spectrometer, both of which exhibit a state-of-the-art sensitivity for cold potassium., Comment: 6 pages + references, 4 figures, accepted for publication in PRA
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- 2017
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9. Studies of general relativity with quantum sensors
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Lefevre, G., Condon, G., Riou, I., Chichet, L., Essayeh, M., Rabault, M., Antoni-Micollier, L., Mielec, N., Holleville, D., Amand, L., Geiger, R., Landragin, A., Prevedelli, M., Barrett, B., Battelier, B., Bertoldi, A., Canuel, B., and Bouyer, P.
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Physics - Atomic Physics ,General Relativity and Quantum Cosmology ,Quantum Physics - Abstract
We present two projects aiming to probe key aspects of the theory of General Relativity with high-precision quantum sensors. These projects use cold-atom interferometry with the aim of measuring gravitational waves and testing the equivalence principle. To detect gravitational waves, a large multi-sensor demonstrator is currently under construction that will exploit correlations between three atom interferometers spread along a 200 m optical cavity. Similarly, a test of the weak equivalence principle is currently underway using a compact and mobile dual-species interferometer, which will serve as a prototype for future high-precision tests onboard an orbiting satellite. We present recent results and improvements related to both projects., Comment: 11 pages, 7 figures, to appear in "Proceedings of the 52nd Rencontres de Moriond on Gravitation"
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- 2017
10. Impact of the emotional development approach on psychotropic medication in adults with intellectual and developmental disabilities: a retrospective clinical analysis.
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Barrett, B. F., Wehmeyer, M., Kolb, J., Ostermann, T., and Sappok, T.
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MENTAL illness drug therapy , *T-test (Statistics) , *AUTISM , *ANTIPSYCHOTIC agents , *RETROSPECTIVE studies , *DESCRIPTIVE statistics , *INTELLECTUAL disabilities , *DEVELOPMENTAL disabilities , *MEDICAL records , *ACQUISITION of data , *ANALYSIS of variance , *INDIVIDUAL development , *ASPERGER'S syndrome , *PSYCHOSES , *ADULTS - Abstract
Background: Compared with the general population, adults with an intellectual developmental disorder (IDD) are more likely to develop mental health problems and to receive high levels of psychotropic medication, particularly antipsychotics. The emotional development (ED) approach may help to better understand the nature of challenging behaviour (CB) and tailor treatment and support accordingly. The aim of this retrospective study was to investigate the impact of the ED approach on the prescription of psychotropic medication during inpatient psychiatric treatment. Methods: The clinical data of 1758 patients were analysed within a retrospective study design over a period of 12 years. ED level was assessed (1) for the first time (INITIAL‐SEO), (2) during a previous hospital stay (PAST‐SEO) or (3) not at all (NO‐SEO). The effects of the ED assessment and the respective intervention during the current admission on the number of psychotropics and the number and dosage of antipsychotics were analysed for the total sample, including those with CB, autism spectrum disorders and psychosis. Group differences were analysed by a chi‐square test and a one‐factorial analysis of variance. For analysing the impact of the application of the ED approach on psychotropic medication, a covariance model was applied. Changes between the subsamples were analysed by t‐tests for dependent samples. Results: The ED approach had a significant impact on reducing the overall amount of psychotropic medication and the dosage of antipsychotics in all patients with IDD. These effects were mainly attributable to those showing CB. In patients with autism spectrum disorders, the developmental approach reduced the number of antipsychotics. No effects could be observed in patients with psychosis; in this subsample, both the number and dosage of antipsychotics increased. Conclusions: The application of the ED approach in the current hospital stay reduced the number of psychotropic drugs and the number and dosage of antipsychotics, especially in those patients with IDD and CB, but also in those with autism spectrum disorders. [ABSTRACT FROM AUTHOR]
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- 2024
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11. Suture Tape Augmentation for the Repair of Index Finger Radial Collateral Ligament Injury: A Biomechanical Study
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Hawthorne, Benjamin C., Wellington, Ian J., Davey, Annabelle P., Torre, Barrett B., Propp, Bennett E., Dorsey, Caitlin G., Obopilwe, Elifho, Ferreira, Joel V., Parrino, Anthony, Rodner, Craig M., and Mazzocca, Augustus D.
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- 2024
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12. Separated kaon electroproduction cross section and the kaon form factor from 6 GeV JLab data
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Carmignotto, M, Ali, S, Aniol, K, Arrington, J, Barrett, B, Beise, EJ, Blok, HP, Boeglin, W, Brash, EJ, Breuer, H, Chang, CC, Christy, ME, Dittmann, A, Ent, R, Fenker, H, Gaskell, D, Gibson, E, Holt, RJ, Horn, T, Huber, GM, Jin, S, Jones, MK, Keppel, CE, Kim, W, King, PM, Kovaltchouk, V, Liu, J, Lolos, GJ, MacK, DJ, Margaziotis, DJ, Markowitz, P, Matsumura, A, Meekins, D, Miyoshi, T, Mkrtchyan, H, Niculescu, G, Niculescu, I, Okayasu, Y, Pegg, IL, Pentchev, L, Perdrisat, C, Potterveld, D, Punjabi, V, Reimer, PE, Reinhold, J, Roche, J, Sarty, A, Smith, GR, Tadevosyan, V, Tang, LG, Trotta, R, Tvaskis, V, Vargas, A, Vidakovic, S, Volmer, J, Vulcan, W, Warren, G, Wood, SA, Xu, C, and Zheng, X
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nucl-ex - Abstract
The H1(e,e′K+)Λ reaction was studied as a function of the Mandelstam variable -t using data from the E01-004 (FPI-2) and E93-018 experiments that were carried out in Hall C at the 6 GeV Jefferson Laboratory. The cross section was fully separated into longitudinal and transverse components, and two interference terms at four-momentum transfers Q2 of 1.00, 1.36, and 2.07GeV2. The kaon form factor was extracted from the longitudinal cross section using the Regge model by Vanderhaeghen et al. [Phys. Rev. C 57, 1454 (1998)PRVCAN0556-281310.1103/PhysRevC.57.1454]. The results establish the method, previously used successfully for pion analyses, for extracting the kaon form factor. Data from 12 GeV Jefferson Laboratory experiments are expected to have sufficient precision to distinguish between theoretical predictions, for example, recent perturbative QCD calculations with modern parton distribution amplitudes. The leading-twist behavior for light mesons is predicted to set in for values of Q2 between 5 and 10GeV2, which makes data in the few-GeV regime particularly interesting. The Q2 dependence at fixed x and -t of the longitudinal cross section that we extracted seems consistent with the QCD factorization prediction within the experimental uncertainty.
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- 2018
13. Development of compact cold-atom sensors for inertial navigation
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Battelier, B., Barrett, B., Fouché, L., Chichet, L., Antoni-Micollier, L., Porte, H., Napolitano, F., Lautier, J., Landragin, A., and Bouyer, P.
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Physics - Atomic Physics - Abstract
Inertial sensors based on cold atom interferometry exhibit many interesting features for applications related to inertial navigation, particularly in terms of sensitivity and long-term stability. However, at present the typical atom interferometer is still very much an experiment---consisting of a bulky, static apparatus with a limited dynamic range and high sensitivity to environmental effects. To be compliant with mobile applications further development is needed. In this work, we present a compact and mobile experiment, which we recently used to achieve the first inertial measurements with an atomic accelerometer onboard an aircraft. By integrating classical inertial sensors into our apparatus, we are able to operate the atomic sensor well beyond its standard operating range, corresponding to half of an interference fringe. We report atom-based acceleration measurements along both the horizontal and vertical axes of the aircraft with one-shot sensitivities of $2.3 \times 10^{-4}\,g$ over a range of $\sim 0.1\,g$. The same technology can be used to develop cold-atom gyroscopes, which could surpass the best optical gyroscopes in terms of long-term sensitivity. Our apparatus was also designed to study multi-axis atom interferometry with the goal of realizing a full inertial measurement unit comprised of the three axes of acceleration and rotation. Finally, we present a compact and tunable laser system, which constitutes an essential part of any cold-atom-based sensor. The architecture of the laser is based on phase modulating a single fiber-optic laser diode, and can be tuned over a range of 1 GHz in less than 200 $\mu$s., Comment: 14 pages + references, 8 figures
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- 2016
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14. Inertial quantum sensors using light and matter
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Barrett, B., Bertoldi, A., and Bouyer, P.
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Physics - Atomic Physics ,General Relativity and Quantum Cosmology ,Physics - Instrumentation and Detectors ,Quantum Physics - Abstract
The past few decades have seen dramatic progress in our ability to manipulate and coherently control matter-waves. Although the duality between particles and waves has been well tested since de Broglie introduced the matter-wave analog of the optical wavelength in 1924, manipulating atoms with a level of coherence that enables one to use these properties for precision measurements has only become possible with our ability to produce atomic samples exhibiting temperatures of only a few millionths of a degree above absolute zero. Since the initial experiments a few decades ago, the field of atom optics has developed in many ways, with both fundamental and applied significance. The exquisite control of matter waves offers the prospect of a new generation of force sensors exhibiting unprecedented sensitivity and accuracy, for applications from navigation and geophysics to tests of general relativity. Thanks to the latest developments in this field, the first commercial products using this quantum technology are now available. In the future, our ability to create large coherent ensembles of atoms will allow us an even more precise control of the matter-wave and the ability to create highly entangled states for non-classical atom interferometry., Comment: 15 pages + references, 9 figures, submitted to Physica Scripta
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- 2016
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15. The No-Core Gamow Shell Model: Including the continuum in the NCSM
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Barrett, B. R., Papadimitriou, G., Michel, N., and Płoszajczak, M.
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Nuclear Theory - Abstract
We are witnessing an era of intense experimental efforts that will provide information about the properties of nuclei far from the line of stability, regarding resonant and scattering states as well as (weakly) bound states. This talk describes our formalism for including these necessary ingredients into the No-Core Shell Model by using the Gamow Shell Model approach. Applications of this new approach, known as the No-Core Gamow Shell Model, both to benchmark cases as well as to unstable nuclei will be given., Comment: 8 pages, 2 figures, 1 table. Proceedings of the "14th International Conference on Nuclear Reaction Mechanisms", Varenna (Italy), June 15-19, 2015
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- 2015
16. Correlative methods for dual-species quantum tests of the weak equivalence principle
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Barrett, B., Antoni-Micollier, L., Chichet, L., Battelier, B., Gominet, P. -A., Bertoldi, A., Bouyer, P., and Landragin, A.
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Physics - Atomic Physics ,Quantum Physics - Abstract
Matter-wave interferometers utilizing different isotopes or chemical elements intrinsically have different sensitivities, and the analysis tools available until now are insufficient for accurately estimating the atomic phase difference under many experimental conditions. In this work, we describe and demonstrate two new methods for extracting the differential phase between dual-species atom interferometers for precise tests of the weak equivalence principle. The first method is a generalized Bayesian analysis, which uses knowledge of the system noise to estimate the differential phase based on a statistical model. The second method utilizes a mechanical accelerometer to reconstruct single-sensor interference fringes based on measurements of the vibration-induced phase. An improved ellipse-fitting algorithm is also implemented as a third method for comparison. These analysis tools are investigated using both numerical simulations and experimental data from simultaneous $^{87}$Rb and $^{39}$K interferometers, and both new techniques are shown to produce bias-free estimates of the differential phase. We also report observations of phase correlations between atom interferometers composed of different chemical species. This correlation enables us to reject common-mode vibration noise by a factor of 730, and to make preliminary tests of the weak equivalence principle with a sensitivity of $1.6 \times 10^{-6}$ per measurement with an interrogation time of $T = 10$ ms. We study the level of vibration rejection by varying the temporal overlap between interferometers in a symmetric timing sequence. Finally, we discuss the limitations of the new analysis methods for future applications of differential atom interferometry., Comment: 38 pages + references, 15 figures, published version
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- 2015
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17. Ab initio effective interactions for sd-shell valence nucleons
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Dikmen, E., Lisetskiy, A. F., Barrett, B. R., Maris, P., Shirokov, A. M., and Vary, J. P.
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Nuclear Theory - Abstract
We perform \textit{ab initio} no-core shell-model calculations for $A=18$ and $19$ nuclei in a $4\hbar\Omega$, or $N_{\rm max}=4$, model space by using the effective JISP16 and chiral N3LO nucleon-nucleon potentials and transform the many-body effective Hamiltonians into the $0\hbar\Omega$ model space to construct the $A$-body effective Hamiltonians in the $sd$-shell. We separate the $A$-body effective Hamiltonians with $A=18$ and $A=19$ into inert core, one-, and two-body components. Then, we use these core, one-, and two-body components to perform standard shell-model calculations for the $A=18$ and $A=19$ systems with valence nucleons restricted to the $sd$ shell. Finally, we compare the standard shell-model results in the $0\hbar\Omega$ model space with the exact no-core shell model results in the $4\hbar\Omega$ model space for the $A=18$ and $A=19$ systems and find good agreement., Comment: 13 pages, 4 figures; revised to include additional figure, correct typos, extend discussions
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- 2015
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18. Separated Response Functions in Exclusive, Forward $\pi^{\pm}$ Electroproduction on Deuterium
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Huber, G. M., Blok, H. P., Butuceanu, C., Gaskell, D., Horn, T., Mack, D. J., Abbott, D., Aniol, K., Anklin, H., Armstrong, C., Arrington, J., Assamagan, K., Avery, S., Baker, O. K., Barrett, B., Beise, E. J., Bochna, C., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Chant, N., Christy, M. E., Dunne, J., Eden, T., Ent, R., Fenker, H., Gibson, E. F., Gilman, R., Gustafsson, K., Hinton, W., Holt, R. J., Jackson, H., Jin, S., Jones, M. K., Keppel, C. E., Kim, P. H., Kim, W., King, P. M., Klein, A., Koltenuk, D., Kovaltchouk, V., Liang, M., Liu, J., Lolos, G. J., Lung, A., Margaziotis, D. J., Markowitz, P., Matsumura, A., McKee, D., Meekins, D., Mitchell, J., Miyoshi, T., Mkrtchyan, H., Mueller, B., Niculescu, G., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Pitz, D., Potterveld, D., Punjabi, V., Qin, L. M., Reimer, P. E., Reinhold, J., Roche, J., Roos, P. G., Sarty, A., Shin, I. K., Smith, G. R., Stepanyan, S., Tang, L. G., Tadevosyan, V., Tvaskis, V., van der Meer, R. L. J., Vansyoc, K., Van Westrum, D., Vidakovic, S., Volmer, J., Vulcan, W., Warren, G., Wood, S. A., Xu, C., Yan, C., Zhao, W. -X., Zheng, X., Zihlmann, B., and Collaboration, The Jefferson Lab Fpi
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Nuclear Experiment - Abstract
Background: Measurements of forward exclusive meson production at different squared four-momenta of the exchanged virtual photon, $Q^2$, and at different four-momentum transfer, t, can be used to probe QCD's transition from meson-nucleon degrees of freedom at long distances to quark-gluon degrees of freedom at short scales. Ratios of separated response functions in $\pi^-$ and $\pi^+$ electroproduction are particularly informative. The ratio for transverse photons may allow this transition to be more easily observed, while the ratio for longitudinal photons provides a crucial verification of the assumed pole dominance, needed for reliable extraction of the pion form factor from electroproduction data. Method: Data were acquired with 2.6-5.2 GeV electron beams and the HMS+SOS spectrometers in Jefferson Lab Hall C, at central $Q^2$ values of 0.6, 1.0, 1.6 GeV$^2$ at W=1.95 GeV, and $Q^2$=2.45 GeV$^2$ at W=2.22 GeV. There was significant coverage in $\phi$ and $\epsilon$, which allowed separation of $\sigma_{L,T,LT,TT}$. Results: $\sigma_L$ shows a clear signature of the pion pole, with a sharp rise at small -t. In contrast, $\sigma_T$ is much flatter versus t. The longitudinal/transverse ratios evolve with $Q^2$ and t, and at the highest $Q^2$=2.45 GeV$^2$ show a slight enhancement for $\pi^-$ production compared to $\pi^+$. The $\pi^-/\pi^+$ ratio for transverse photons exhibits only a small $Q^2$-dependence, following a nearly universal curve with t, with a steep transition to a value of about 0.25, consistent with s-channel quark knockout. The $\sigma_{TT}/\sigma_T$ ratio also drops rapidly with $Q^2$, qualitatively consistent with s-channel helicity conservation. The $\pi^-/\pi^+$ ratio for longitudinal photons indicates a small isoscalar contamination at W=1.95 GeV, consistent with what was observed in our earlier determination of the pion form factor at these kinematics., Comment: 25 pages, 16 figures, 6 tables
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- 2014
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19. Epidemiology and trends of adult ice hockey injuries presenting to United States emergency departments: A ten-year analysis from 2007–2016
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Morrissey, Patrick J., Maier, Stephen P., II, Zhou, Jack J., Sedaghatpour, Dillon, Shah, Neil V., Torre, Barrett B., Beaufort, Andrew, Chatterjee, Dipal, Doran, James P., and Urban, William P., Jr.
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- 2020
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20. A brief version of the Scale of Emotional Development – Short
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Sappok, T., primary, Barrett, B., additional, and Lutter, S., additional
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- 2024
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21. VISUAL & ACOUSTIC FACTORS AFFECTING THE ASSESSMENT OF TRANQUILITY
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PHEASANT, R, primary, BARRETT, B, additional, HOROSHENKOV, K, additional, and WATTS, G, additional
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- 2023
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22. Separated Response Function Ratios in Exclusive, Forward pi^{+/-} Electroproduction
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Huber, G. M., Blok, H. P., Butuceanu, C., Gaskell, D., Horn, T., Mack, D. J., Abbott, D., Aniol, K., Anklin, H., Armstrong, C., Arrington, J., Assamagan, K., Avery, S., Baker, O. K., Barrett, B., Beise, E. J., Bochna, C., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Chant, N., Christy, M. E., Dunne, J., Eden, T., Ent, R., Fenker, H., Gibson, E. F., Gilman, R., Gustafsson, K., Hinton, W., Holt, R. J., Jackson, H., Jin, S., Jones, M. K., Keppel, C. E., Kim, P. H., Kim, W., King, P. M., Klein, A., Koltenuk, D., Kovaltchouk, V., Liang, M., Liu, J., Lolos, G. J., Lung, A., Margaziotis, D. J., Markowitz, P., Matsumura, A., McKee, D., Meekins, D., Mitchell, J., Miyoshi, T., Mkrtchyan, H., Mueller, B., Niculescu, G., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Pitz, D., Potterveld, D., Punjabi, V., Qin, L. M., Reimer, P. E., Reinhold, J., Roche, J., Roos, P. G., Sarty, A., Shin, I. K., Smith, G. R., Stepanyan, S., Tang, L. G., Tadevosyan, V., Tvaskis, V., van der Meer, R. L. J., Vansyoc, K., Van Westrum, D., Vidakovic, S., Volmer, J., Vulcan, W., Warren, G., Wood, S. A., Xu, C., Yan, C., Zhao, W. -X., Zheng, X., and Zihlmann, B.
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Nuclear Experiment - Abstract
The study of exclusive $\pi^{\pm}$ electroproduction on the nucleon, including separation of the various structure functions, is of interest for a number of reasons. The ratio $R_L=\sigma_L^{\pi^-}/\sigma_L^{\pi^+}$ is sensitive to isoscalar contamination to the dominant isovector pion exchange amplitude, which is the basis for the determination of the charged pion form factor from electroproduction data. A change in the value of $R_T=\sigma_T^{\pi^-}/\sigma_T^{\pi^+}$ from unity at small $-t$, to 1/4 at large $-t$, would suggest a transition from coupling to a (virtual) pion to coupling to individual quarks. Furthermore, the mentioned ratios may show an earlier approach to pQCD than the individual cross sections. We have performed the first complete separation of the four unpolarized electromagnetic structure functions above the dominant resonances in forward, exclusive $\pi^{\pm}$ electroproduction on the deuteron at central $Q^2$ values of 0.6, 1.0, 1.6 GeV$^2$ at $W$=1.95 GeV, and $Q^2=2.45$ GeV$^2$ at $W$=2.22 GeV. Here, we present the $L$ and $T$ cross sections, with emphasis on $R_L$ and $R_T$, and compare them with theoretical calculations. Results for the separated ratio $R_L$ indicate dominance of the pion-pole diagram at low $-t$, while results for $R_T$ are consistent with a transition between pion knockout and quark knockout mechanisms., Comment: 6 pages, 3 figures
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- 2014
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23. Mobile and remote inertial sensing with atom interferometers
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Barrett, B., Gominet, P. -A., Cantin, E., Antoni-Micollier, L., Bertoldi, A., Battelier, B., Bouyer, P., Lautier, J., and Landragin, A.
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Physics - Atomic Physics ,Physics - Geophysics ,Physics - Space Physics - Abstract
The past three decades have shown dramatic progress in the ability to manipulate and coherently control the motion of atoms. This exquisite control offers the prospect of a new generation of inertial sensors with unprecedented sensitivity and accuracy, which will be important for both fundamental and applied science. In this article, we review some of our recent results regarding the application of atom interferometry to inertial measurements using compact, mobile sensors. This includes some of the first interferometer measurements with cold $^{39}$K atoms, which is a major step toward achieving a transportable, dual-species interferometer with rubidium and potassium for equivalence principle tests. We also discuss future applications of this technology, such as remote sensing of geophysical effects, gravitational wave detection, and precise tests of the weak equivalence principle in Space., Comment: 63 pages, 35 figures, to be published in Proceedings of the International School of Physics "Enrico Fermi", Course 188 on Atom Interferometry (2014)
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- 2013
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24. Reducing perioperative blood loss with antifibrinolytics and antifibrinolytic-like agents for patients undergoing total hip and total knee arthroplasty
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Kapadia, Bhaveen H., Torre, Barrett B., Ullman, Nicholas, Yang, Andrew, Harb, Matthew A., Grieco, Preston W., Newman, Jared M., Harwin, Steven F., and Maheshwari, Aditya V.
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- 2019
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25. Circulating Interleukin-6 is Associated with Skeletal Muscle Strength, Quality, and Functional Adaptation with Exercise Training in Mobility-Limited Older Adults
- Author
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Grosicki, Gregory J., Barrett, B. B., Englund, D. A., Liu, C., Travison, T. G., Cederholm, T., Koochek, A., von Berens, Å., Gustafsson, T., Benard, T., Reid, K. F., and Fielding, R. A.
- Published
- 2020
- Full Text
- View/download PDF
26. Demonstration of improved sensitivity of echo interferometers to gravitational acceleration
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Mok, C., Barrett, B., Carew, A., Berthiaume, R., Beattie, S., and Kumarakrishnan, A.
- Subjects
Physics - Atomic Physics - Abstract
We have developed two configurations of an echo interferometer that rely on standing wave excitation of a laser-cooled sample of rubidium atoms that measures acceleration. For a two-pulse configuration, the interferometer signal is modulated at the recoil frequency and exhibits a sinusoidal frequency chirp as a function of pulse spacing. For a three-pulse stimulated echo configuration, the signal is observed without recoil modulation and exhibits a modulation at a single frequency. The three-pulse configuration is less sensitive to effects of vibrations and magnetic field curvature leading to a longer experimental timescale. For both configurations of the atom interferometer (AI), we show that a measurement of acceleration with a statistical precision of 0.5% can be realized by analyzing the shape of the echo envelope that has a temporal duration of a few microseconds. Using the two-pulse AI, we obtain measurements of acceleration that are statistically precise to 6 parts per million (ppm) on a 25 ms timescale. Using the three-pulse AI, we obtain measurements of acceleration that are statistically precise to 0.4 ppm on a timescale of 50 ms. A further statistical enhancement is achieved by analyzing the data across the echo envelope to improve the statistical precision to 75 parts per billion (ppb). We discuss methods for reducing prominent systematic effects due to a magnetized vacuum chamber and improving the signal-to-noise ratio. Simulations of both AI configurations with a timescale of 300 ms reached in a non-magnetic vacuum chamber suggest that an optimized experiment with improved vibration isolation and atoms selected in the mF = 0 state can result in measurements of g statistically precise to 0.3 pbb for the two-pulse AI and 0.6 ppb for the three-pulse AI., Comment: 17 pages, 9 figures, 3 tables
- Published
- 2013
- Full Text
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27. Extrapolation uncertainties in the importance-truncated No-Core Shell Model
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Kruse, M. K. G., Jurgenson, E. D., Navrátil, P., Barrett, B. R., and Ormand, W. E.
- Subjects
Nuclear Theory - Abstract
We report on Li-6 calculations performed with the IT-NCSM and compare them to full NCSM calculations. We employ the Entem and Machleidt chiral two-body N3LO interaction (regulated at 500 MeV/c), which has been modified to a phase-shift equivalent potential by the similarity renormalization group (SRG) procedure. We investigate the dependence of the procedure on the technique employed to extrapolate to the complete Nmax space, the harmonic oscillator energy, and investigate the dependence on the momentum-decoupling scale (\lambda) used in the SRG. We also investigate the use of one or several reference states from which the truncated basis is constructed. We find that the uncertainties generated from various extrapolating functions used to extrapolate to the complete Nmax space increase as Nmax increases. The extrapolation uncertainties range from a few keV for the smallest Nmax spaces to about 50 keV for the largest Nmax spaces. We note that the difference between extrapolated IT-NCSM and NCSM ground-state energies, however, can be as large as a 100-250 keV depending on the chosen harmonic oscillator energy. We also present the extrapolation of IT-NCSM results to Nmax infinity and compare these to similarly extrapolated full NCSM results., Comment: 22 pages, 12 figures
- Published
- 2013
- Full Text
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28. Ab-initio No-Core Gamow Shell Model calculations with realistic interactions
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Papadimitriou, G., Rotureau, J., Michel, N., Płoszajczak, M., and Barrett, B. R.
- Subjects
Nuclear Theory - Abstract
No-Core Gamow Shell Model (NCGSM) is applied for the first time to study selected well-bound and unbound states of helium isotopes. This model is formulated on the complex energy plane and, by using a complete Berggren ensemble, treats bound, resonant, and scattering states on equal footing. We use the Density Matrix Renormalization Group method to solve the many-body Schr\"{o}dinger equation. To test the validity of our approach, we benchmarked the NCGSM results against Faddeev and Faddeev-Yakubovsky exact calculations for $^3$H and $^4$He nuclei. We also performed {\textit ab initio} NCGSM calculations for the unstable nucleus $^5$He and determined the ground state energy and decay width, starting from a realistic N$^3$LO chiral interaction., Comment: 17 pages, 14 figures. Revised version. Discussion on microscopic overlap functions, SFs and ANCs is added. Added references. Accepted for publication at PRC
- Published
- 2013
- Full Text
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29. Using LIDAR for Forage Yield Measurement of Perennial Ryegrass (Lolium perenne L.) Field Plots
- Author
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Ghamkhar, K., Irie, K., Hagedorn, M., Hsiao, J., Fourie, J., Gebbie, S., Flay, C., Barrett, B., Stewart, A., Werner, A., Brazauskas, Gintaras, editor, Statkevičiūtė, Gražina, editor, and Jonavičienė, Kristina, editor
- Published
- 2018
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30. Measuring the atomic recoil frequency using a perturbative grating-echo atom interferometer
- Author
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Barrett, B., Carew, A., Beattie, S., and Kumarakrishnan, A.
- Subjects
Physics - Atomic Physics - Abstract
We describe progress toward a precise measurement of the recoil energy of an atom measured using a perturbative grating-echo atom interferometer (AI) that involves three standing-wave (sw) pulses. With this technique, a perturbing sw pulse is used to shift the phase of excited momentum states---producing a modulation in the contrast of the interference pattern. The signal exhibits narrow fringes that revive periodically at twice the two-photon recoil frequency, $2\omega_q$, as a function of the onset time of the pulse. Experiments are performed using samples of laser-cooled rubidium atoms with temperatures $\lesssim 5$ $\mu$K in a non-magnetic apparatus. We demonstrate a measurement of $\omega_q$ with a statistical uncertainty of 37 parts per $10^9$ (ppb) on a time scale of $\sim 45$ ms in 14 hours. Further statistical improvements are anticipated by extending this time scale and narrowing the signal fringe width. However, the total systematic uncertainty is estimated to be $\sim 6$ parts per $10^6$ (ppm). We describe methods of reducing these systematic errors., Comment: 8 pages, 5 figures, submitted to PRA
- Published
- 2012
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31. Two and Three Nucleons in a Trap and the Continuum Limit
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Rotureau, J., Stetcu, I., Barrett, B. R., and van Kolck, U.
- Subjects
Nuclear Theory - Abstract
We describe systems of two and three nucleons trapped in a harmonic-oscillator potential with interactions from the pionless effective field theory up to next-to-leading order (NLO). We construct the two-nucleon interaction using two-nucleon scattering information. We calculate the trapped levels in the three-nucleon system with isospin $T=1/2$ and determine the three-nucleon force needed for stability of the triton. We extract neutron-deuteron phase shifts, and show that the quartet scattering length is in good agreement with experimental data., Comment: 19 pages, 15 figures
- Published
- 2011
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- View/download PDF
32. Atom interferometric techniques for measuring uniform magnetic field gradients and gravitational acceleration
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Barrett, B., Chan, I., and Kumarakrishnan, A.
- Subjects
Physics - Atomic Physics ,Quantum Physics - Abstract
We discuss techniques for probing the effects of a constant force acting on cold atoms using two configurations of a grating echo-type atom interferometer. Laser-cooled samples of $^{85}$Rb with temperatures as low as 2.4 $\mu$K have been achieved in a new experimental apparatus with a well-controlled magnetic environment. We demonstrate interferometer signal lifetimes approaching the transit time limit in this system ($\sim 270$ ms), which is comparable to the timescale achieved by Raman interferometers. Using these long timescales, we experimentally investigate the influence of a homogeneous magnetic field gradient using two- and three-pulse interferometers, which enable us to sense changes in externally applied magnetic field gradients as small as $\sim 4 \times 10^{-5}$ G/cm. We also provide an improved theoretical description of signals generated by both interferometer configurations that accurately models experimental results. With this theory, absolute measurements of $B$-gradients at the level of $3 \times 10^{-4}$ G/cm are achieved. Finally, we contrast the suitability of the two- and three-pulse interferometers for precision measurements of the gravitational acceleration, $g$., Comment: 18 pages, 9 figures, accepted for publication in Physical Review A
- Published
- 2011
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33. Three and Four Harmonically Trapped Particles in an Effective Field Theory Framework
- Author
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Rotureau, J., Stetcu, I., Barrett, B. R., Birse, M. C., and van Kolck, U.
- Subjects
Condensed Matter - Quantum Gases ,Nuclear Theory - Abstract
We study systems of few two-component fermions interacting via short-range interactions within a harmonic-oscillator trap. The dominant interactions, which are two-body, are organized according to the number of derivatives and defined in a two-body truncated model space made from a bound-state basis. Leading-order (LO) interactions are solved for exactly using the formalism of the No-Core Shell Model, whereas corrections are treated as many-body perturbations. We show explicitly that next-to-LO and next-to-next-to-LO interactions improve convergence as the model space increases. We present results at unitarity for three- and four-fermion systems, which show excellent agreement with the exact solution (for the three-body problem) and results obtained by others methods (in the four-body case). We also present results for finite scattering lengths and non-zero range of the interaction, including (at positive scattering length) observation of a change in the structure of the three-body ground state and extraction of the atom-dimer scattering length., Comment: 18 pages, 10 figures
- Published
- 2010
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34. Spin density matrices for nuclear density functionals with parity violations
- Author
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Barrett, B. R. and Giraud, B. G.
- Subjects
Nuclear Theory - Abstract
The spin density matrix (SDM) used in atomic and molecular physics is revisited for nuclear physics, in the context of the radial density functional theory. The vector part of the SDM defines a "hedgehog" situation, which exists only if nuclear states contain some amount of parity violation., Comment: 8 pages, 2 figures
- Published
- 2010
35. An effective field theory approach to two trapped particles
- Author
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Stetcu, I., Rotureau, J., Barrett, B. R., and van Kolck, U.
- Subjects
Condensed Matter - Quantum Gases ,Nuclear Theory - Abstract
We discuss the problem of two particles interacting via short-range interactions within a harmonic-oscillator trap. The interactions are organized according to their number of derivatives and defined in truncated model spaces made from a bound-state basis. Leading-order (LO) interactions are iterated to all orders, while corrections are treated in perturbation theory. We show explicitly that next-to-LO and next-to-next-to-LO interactions improve convergence as the model space increases. In the large-model-space limit we regain results from a pseudopotential. Arbitrary scattering lengths are considered, as well as a generalization to include the non-vanishing range of the interaction., Comment: 27 pages, 12 figures
- Published
- 2010
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36. Effective interactions for light nuclei: an effective (field theory) approach
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Stetcu, I., Rotureau, J., Barrett, B. R., and van Kolck, U.
- Subjects
Nuclear Theory - Abstract
One of the central open problems in nuclear physics is the construction of effective interactions suitable for many-body calculations. We discuss a recently developed approach to this problem, where one starts with an effective field theory containing only fermion fields and formulated directly in a no-core shell-model space. We present applications to light nuclei and to systems of a few atoms in a harmonic-oscillator trap. Future applications and extensions, as well as challenges, are also considered.
- Published
- 2009
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37. Effective operators from exact many-body renormalization
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Lisetskiy, A. F., Kruse, M. K. G., Barrett, B. R., Navratil, P., Stetcu, I., and Vary, J. P.
- Subjects
Nuclear Theory - Abstract
We construct effective two-body Hamiltonians and E2 operators for the p-shell by performing $16\hbar\Omega$ ab initio no-core shell model (NCSM) calculations for A=5 and A=6 nuclei and explicitly projecting the many-body Hamiltonians and E2 operator onto the $0\hbar\Omega$ space. We then separate the effective E2 operator into one-body and two-body contributions employing the two-body valence cluster approximation. We analyze the convergence of proton and neutron valence one-body contributions with increasing model space size and explore the role of valence two-body contributions. We show that the constructed effective E2 operator can be parametrized in terms of one-body effective charges giving a good estimate of the NCSM result for heavier p-shell nuclei., Comment: 9 pages, 8 figures
- Published
- 2009
- Full Text
- View/download PDF
38. Ab initio shell-model calculation for ^{18}O in a restricted no-core model space
- Author
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Fujii, S. and Barrett, B. R.
- Subjects
Nuclear Theory - Abstract
We perform an ab initio shell-model calculation for ^{18}O in a restricted no-core model space, microscopically deriving a two-body effective interaction and introducing a minimal refinement of one-body energies in the spsd or spsdpf model space. Low-lying energy levels, except for the experimental 0_{2}^{+} and 2_{3}^{+} states, are better described in the spsdpf space than in the spsd space. The structure of low-lying energy levels is discussed with an emphasis on many-particle many-hole states beyond the four-particle two-hole configuration., Comment: 4 pages, 2 figures
- Published
- 2009
39. Brief report comparing the Scale of Emotional Development – Short (SED‐S) with other scales for emotional development
- Author
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Sappok, T., primary, Morisse, F., additional, Flachsmeyer, M., additional, Vandevelde, S., additional, Ilic, M., additional, and Barrett, B. F., additional
- Published
- 2023
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- View/download PDF
40. Scale of Emotional Development – Short: reliability and validity in adults with intellectual disability
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Flachsmeyer, M., primary, Sterkenburg, P., additional, Barrett, B., additional, Zaal, S., additional, Vonk, J., additional, Morisse, F., additional, Gaese, F., additional, Heinrich, M., additional, and Sappok, T., additional
- Published
- 2023
- Full Text
- View/download PDF
41. Charged pion form factor between $Q^2$=0.60 and 2.45 GeV$^2$. I. Measurements of the cross section for the ${^1}$H($e,e'\pi^+$)$n$ reaction
- Author
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Blok, H. P., Horn, T., Huber, G. M., Beise, E. J., Gaskell, D., Mack, D. J., Tadevosyan, V., Volmer, J., Abbott, D., Aniol, K., Anklin, H., Armstrong, C., Arrington, J., Assamagan, K., Avery, S., Baker, O. K., Barrett, B., Bochna, C., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Chant, N., Christy, M. E., Dunne, J., Eden, T., Ent, R., Fenker, H., Gibson, E., Gilman, R., Gustafsson, K., Hinton, W., Holt, R. J., Jackson, H., Jin, S., Jones, M. K., Keppel, C. E., Kim, P. H., Kim, W., King, P. M., Klein, A., Koltenuk, D., Kovaltchouk, V., Liang, M., Liu, J., Lolos, G. J., Lung, A., Margaziotis, D. J., Markowitz, P., Matsumura, A., McKee, D., Meekins, D., Mitchell, J., Miyoshi, T., Mkrtchyan, H., Mueller, B., Niculescu, G., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Pitz, D., Potterveld, D., Punjabi, V., Qin, L. M., Reimer, P., Reinhold, J., Roche, J., Roos, P. G., Sarty, A., Shin, I. K., Smith, G. R., Stepanyan, S., Tang, L. G., Tvaskis, V., van der Meer, R. L. J., Vansyoc, K., Van Westrum, D., Vidakovic, S., Vulcan, W., Warren, G., Wood, S. A., Xu, C., Yan, C., Zhao, W. -X., Zheng, X., and Zihlmann, B.
- Subjects
Nuclear Experiment - Abstract
Cross sections for the reaction ${^1}$H($e,e'\pi^+$)$n$ were measured in Hall C at Thomas Jefferson National Accelerator Facility (JLab) using the CEBAF high-intensity, continous electron beam in order to determine the charged pion form factor. Data were taken for central four-momentum transfers ranging from $Q^2$=0.60 to 2.45 GeV$^2$ at an invariant mass of the virtual photon-nucleon system of $W$=1.95 and 2.22 GeV. The measured cross sections were separated into the four structure functions $\sigma_L$, $\sigma_T$, $\sigma_{LT}$, and $\sigma_{TT}$. The various parts of the experimental setup and the analysis steps are described in detail, including the calibrations and systematic studies, which were needed to obtain high precision results. The different types of systematic uncertainties are also discussed. The results for the separated cross sections as a function of the Mandelstam variable $t$ at the different values of $Q^2$ are presented. Some global features of the data are discussed, and the data are compared with the results of some model calculations for the reaction ${^1}$H($e,e'\pi^+$)$n$., Comment: 26 pages, 23 figures
- Published
- 2008
- Full Text
- View/download PDF
42. Charged pion form factor between Q^2=0.60 and 2.45 GeV^2. II. Determination of, and results for, the pion form factor
- Author
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Huber, G. M., Blok, H. P., Horn, T., Beise, E. J., Gaskell, D., Mack, D. J., Tadevosyan, V., Volmer, J., Abbott, D., Aniol, K., Anklin, H., Armstrong, C., Arrington, J., Assamagan, K., Avery, S., Baker, O. K., Barrett, B., Bochna, C., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Chant, N., Christy, M. E., Dunne, J., Eden, T., Ent, R., Gibson, E., Gilman, R., Gustafsson, K., Hinton, W., Holt, R. J., Jackson, H., Jin, S., Jones, M. K., Keppel, C. E., Kim, P. H., Kim, W., King, P. M., Klein, A., Koltenuk, D., Kovaltchouk, V., Kiang, M., Liu, J., Lolos, G. J., Lung, A., Margaziotis, D. J., Markowitz, P., Matsumura, A., McKee, D., Meekins, D., Mitchell, J., Miyoshi, T., Mkrtchyan, H., Mueller, B., Niculescu, G., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Pitz, D., Potterveld, D., Punjabi, V., Qin, L. M., Reimer, P., Reinhold, J., Roche, J., Roos, P. G., Sarty, A., Shin, I. K., Smith, G. R., Stepanyan, S., Tang, L. G., Tvaskis, V., van der Meer, R. L. J., Vansyoc, K., Van Westrum, D., Vidakovic, S., Vulcan, W., Warren, G., Wood, S. A., Xu, C., Yan, C., Zhao, W. -X., Zheng, X., and Zihlmann, B.
- Subjects
Nuclear Experiment - Abstract
The charged pion form factor, Fpi(Q^2), is an important quantity which can be used to advance our knowledge of hadronic structure. However, the extraction of Fpi from data requires a model of the 1H(e,e'pi+)n reaction, and thus is inherently model dependent. Therefore, a detailed description of the extraction of the charged pion form factor from electroproduction data obtained recently at Jefferson Lab is presented, with particular focus given to the dominant uncertainties in this procedure. Results for Fpi are presented for Q^2=0.60-2.45 GeV^2. Above Q^2=1.5 GeV^2, the Fpi values are systematically below the monopole parameterization that describes the low Q^2 data used to determine the pion charge radius. The pion form factor can be calculated in a wide variety of theoretical approaches, and the experimental results are compared to a number of calculations. This comparison is helpful in understanding the role of soft versus hard contributions to hadronic structure in the intermediate Q^2 regime., Comment: 18 pages, 11 figures
- Published
- 2008
- Full Text
- View/download PDF
43. Determining the Energy Barrier for Decay out of Superdeformed Bands
- Author
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Barrett, B. R., Bürki, J., Cardamone, D. M., Stafford, C. A., and Stein, D. L.
- Subjects
Nuclear Theory - Abstract
An asymptotically exact quantum mechanical calculation of the matrix elements for tunneling through an asymmetric barrier is combined with the two-state statistical model for decay out of superdeformed bands to determine the energy barrier (as a function of spin) separating the superdeformed and normal-deformed wells for several nuclei in the 190 and 150 mass regions. The spin-dependence of the barrier leading to sudden decay out is shown to be consistent with the decrease of a centrifugal barrier with decreasing angular momentum. Values of the barrier frequency in the two mass regions are predicted., Comment: v1: 4 pages, 1 figure, 1 table. v2: 5 pages, 1 figure, 1 table; minor corrections and clarifications
- Published
- 2008
- Full Text
- View/download PDF
44. Ab-initio shell model with a core
- Author
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Lisetskiy, A. F., Barrett, B. R., Kruse, M. K. G., Navratil, P., Stetcu, I., and Vary, J. P.
- Subjects
Nuclear Theory - Abstract
We construct effective 2- and 3-body Hamiltonians for the p-shell by performing 12\hbar\Omega ab initio no-core shell model (NCSM) calculations for A=6 and 7 nuclei and explicitly projecting the many-body Hamiltonians onto the 0\hbar\Omega space. We then separate these effective Hamiltonians into 0-, 1- and 2-body contributions (also 3-body for A=7) and analyze the systematic behavior of these different parts as a function of the mass number A and size of the NCSM basis space. The role of effective 3- and higher-body interactions for A>6 is investigated and discussed.
- Published
- 2008
- Full Text
- View/download PDF
45. Detecting and quantifying morphological change in tropical rivers using Google Earth Engine and image analysis techniques
- Author
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Boothroyd, R.J., primary, Williams, R.D., additional, Barrett, B., additional, Hoey, T.B., additional, Tolentino, P.L.M., additional, Perez, J.E., additional, Guardian, E., additional, David, C.P., additional, and Yang, X., additional
- Published
- 2020
- Full Text
- View/download PDF
46. Bounds to binding energies from the concavity of thermodynamical functions
- Author
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Jennings, B. K., Barrett, B. R., and Giraud, B. G.
- Subjects
Nuclear Theory - Abstract
Sequences of experimental ground-state energies are mapped onto concave patterns cured from convexities due to pairing and/or shell effects. The same patterns, completed by a list of excitation energies, can be used to give numerical estimates of the grand potential $\Omega(\beta,\mu)$ for a mixture of nuclei at low or moderate temperatures $T=\beta^{-1}$ and at many chemical potentials $\mu.$ The average nucleon number $<{\bf A} >(\beta,\mu)$ then becomes a continuous variable, allowing extrapolations towards nuclear masses closer to drip lines. We study the possible concavity of several thermodynamical functions, such as the free energy and the average energy, as functions of $<{\bf A} >.$ Concavity, when present in such functions, allows trivial interpolations and extrapolations providing upper and lower bounds, respectively, to binding energies. Such bounds define an error bar for the prediction of binding energies. An extrapolation scheme for such concave functions is tested. We conclude with numerical estimates of the binding energies of a few nuclei closer to drip lines., Comment: 13 pages, including 4 double figures and 5 simple figures
- Published
- 2007
47. Concavity for nuclear binding energies, thermodynamical functions and density functionals
- Author
-
Barrett, B. R., Giraud, B. G., Jennings, B. K., and Toberg, N. P.
- Subjects
Nuclear Theory - Abstract
Sequences of experimental ground-state energies for both odd and even $A$ are mapped onto concave patterns cured from convexities due to pairing and/or shell effects. The same patterns, completed by a list of excitation energies, give numerical estimates of the grand potential $\Omega(\beta,\mu)$ for a mixture of nuclei at low or moderate temperatures $T=\beta^{-1}$ and at many chemical potentials $\mu.$ The average nucleon number $<{\bf A} >(\beta,\mu)$ then becomes a continuous variable, allowing extrapolations towards nuclear masses closer to drip lines. We study the possible concavity of several thermodynamical functions, such as the free energy and the average energy, as functions of $<{\bf A} >.$ Concavity, which always occur for the free energy and is usually present for the average energy, allows easy interpolations and extrapolations providing upper and lower bounds, respectively, to binding energies. Such bounds define an error bar for the prediction of binding energies. Finally we show how concavity and universality are related in the theory of the nuclear density functional., Comment: 19 pages, 12 figures, revised manuscript resubmitted for publication
- Published
- 2007
48. Existence of a Density Functional for an Intrinsic State
- Author
-
Giraud, B. G., Jennings, B. K., and Barrett, B. R.
- Subjects
Nuclear Theory ,Mathematical Physics - Abstract
A generalization of the Hohenberg-Kohn theorem proves the existence of a density functional for an intrinsic state, symmetry violating, out of which a physical state with good quantum numbers can be projected., Comment: 6 pages
- Published
- 2007
- Full Text
- View/download PDF
49. Effective Theory for Trapped Few-Fermion Systems
- Author
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Stetcu, I., Barrett, B. R., van Kolck, U., and Vary, J. P.
- Subjects
Condensed Matter - Other Condensed Matter ,Nuclear Theory ,Physics - Atomic Physics - Abstract
We apply the general principles of effective field theories to the construction of effective interactions suitable for few- and many-body calculations in a no-core shell model framework. We calculate the spectrum of systems with three and four two-component fermions in a harmonic trap. In the unitary limit, we find that three-particle results are within 10% of known semi-analytical values even in small model spaces. The method is very general, and can be readily extended to other regimes, more particles, different species (e.g., protons and neutrons in nuclear physics), or more-component fermions (as well as bosons). As an illustration, we present calculations of the lowest-energy three-fermion states away from the unitary limit and find a possible inversion of parity in the ground state in the limit of trap size large compared to the scattering length. Furthermore, we investigate the lowest positive-parity states for four fermions, although we are limited by the dimensions we can currently handle in this case., Comment: 8 pages, 5 figures
- Published
- 2007
- Full Text
- View/download PDF
50. Universality of Decay out of Superdeformed Bands in the 190 Mass Region
- Author
-
Cardamone, D. M., Barrett, B. R., and Stafford, C. A.
- Subjects
Nuclear Theory - Abstract
Superdeformed nuclei in the 190 mass region exhibit a striking universality in their decay-out profiles. We show that this universality can be explained in the two-level model of superdeformed decay as related to a strong separation of energy scales: a higher scale related to the nuclear interactions, and a lower scale caused by electromagnetic decay. Furthermore, we present the results of the two-level model for all decays for which sufficient data are known, including statistical extraction of the matrix element for tunneling through the potential barrier., Comment: 7 pages, 3 figures. v2: some minor clarifications, minor correction to Fig. 2
- Published
- 2007
- Full Text
- View/download PDF
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