Search

An analysis of the direct correlation functions $c_{ij} (r)$ of binary additive hard-sphere mixtures of diameters $\sigma_s$ and $\sigma_b$ (where the subscripts $s$ and $b$ refer to the "small" and "big" spheres, respectively), as obtained with the rational-function approximation method and the WM scheme introduced in previous work [S.\ Pieprzyk \emph{et al.}, Phys.\ Rev.\ E {\bf 101}, 012117 (2020)], is performed. The results indicate that the functions $c_{ss}(r, Comment: 11 pages, 8 figures

The authors developed a highly sensitive method based on a quantum-control double-resonance-spectroscopy scheme to study electronically excited states of molecular ions that do not dissociate. The method is used to study the $3d\phantom{\rule{0}{0ex}}\ensuremath{\delta}$ Rydberg state of MgAr${}^{+}$, and the results contribute to the first extensive characterization of the Rydberg states of a molecular cation.

One of the most important and useful entropic uncertainty relations concerns a $d$ dimensional system and two mutually unbiased measurements. In such a setting, the sum of two information entropies is lower bounded by $\ln d$. It has recently been shown that projective measurements subject to operational mutual unbiasedness can also be constructed in a continuous domain, with the help of periodic coarse graining. Here we consider the whole family of R\'enyi entropies applied to these discretized observables and prove that such a scheme does also admit the uncertainty relation mentioned above., Comment: 7 pages, submitted to PRA

I derive an exact integral expression for the ratio of shear viscosity over entropy density $\frac{\eta}{s}$ for the massless (critical) O(N) model at large N with quartic interactions. The calculation is set up and performed entirely from the field theory side using a non-perturbative resummation scheme that captures all contributions to leading order in large N. In 2+1d, $\frac{\eta}{s}$ is evaluated numerically at all values of the coupling. For infinite coupling, I find $\frac{\eta}{s}\simeq 0.42(1)\times N$. I show that this strong coupling result for the viscosity is universal for a large class of interacting bosonic O(N) models., Comment: 6 pages, 1 figure plus supplemental material; v2: fixed typos and buggy code for (84) in v1, corrected eta/s values; v3: typo in (9) corrected, Fig.1 updated (no change in results)

Maximally entangled states play a central role in quantum information processing. Despite much progress throughout the years, robust protocols for manipulations of such states in many-level systems are still scarce. Here we present a control scheme that allows efficient manipulation of complete population inversion between two maximally entangled states. Exploiting the self-duality of $\mathrm{SU}(2)$, we present in this work a family of ${2}^{2N}$-level systems with couplings related to Pythagorean triples that make a complete population inversion from one state to another (orthogonal) state, using very few couplings and generators. We relate our method to the recently developed retrograde-canon scheme and derive a more general complete transfer recipe. We also discuss the cases of ${(2n)}^{2}$-level systems, ${(2n+1)}^{2}$-level systems, and other unitary groups, and give a geometrical description of the inversion via the Majorana sphere.

We compute the logarithmic contributions to the polarized massive Wilson coefficients for deep-inelastic scattering in the asymptotic region ${Q}^{2}\ensuremath{\gg}{m}^{2}$ to three-loop order in the fixed-flavor number scheme and present the corresponding expressions for the polarized massive operator matrix elements needed in the variable flavor number scheme. The calculation is performed in the Larin scheme. For the massive operator matrix elements ${A}_{qq,Q}^{(3),\mathrm{PS}}$ and ${A}_{qg,Q}^{(3),\mathrm{S}}$ the complete results are presented. The expressions are given in Mellin-$N$ space and in momentum fraction $z$ space.

We discuss the effect that small fluctuations of both local anisotropy and energy density, may have on the occurrence of cracking in spherical compact objects satisfying a polytropic equation of state. A systematic scheme to bring the fluid configurations out of hydrostatic equilibrium is revisited. Various models of polytropes are considered and it is shown that departures from equilibrium may lead to the appearance of cracking for a wide range of values of the parameters involved. Prospective applications of the obtained results to some astrophysical scenarios are pointed out., 15 pages; 14 figures. Version published at PRD

In this paper, we present our study on the $T\overline{T}$ deformation of nonrelativistic complex scalar field theory. We find the closed form of the deformed Lagrangian by using the perturbation and the method of characteristics. Furthermore we compute the exact energy spectrum of the deformed free theory by using the Brillouin-Wigner perturbation theory in an appropriate regularization scheme.

Symmetries offer simple solutions to complex problems: A permutation scheme allows solving high complexity problems in quantum chemistry with simple and short quantum circuits.

Recently, higher-order topologies have been experimentally realized, featuring topological corner modes (TCMs) between adjacent topologically distinct domains. However, they have to comply with specific spatial symmetries of underlying lattices, hence their TCMs only emerge in very limited geometries, which significantly impedes generic applications. Here, we report a general scheme of inducing TCMs in arbitrary geometry based on Dirac vortices from aperiodic Kekul\'e modulations. The TCMs can now be constructed and experimentally observed in square and pentagonal domains incompatible with underlying triangular lattices. Such bound modes at arbitrary corners do not require their boundaries to run along particular lattice directions. Our scheme allows an arbitrary specification of numbers and positions of TCMs, which will be important for future on-chip topological circuits. Moreover, the general scheme developed here can be extended to other classical wave systems. Our findings reveal rich physics of aperiodic modulations, and advance applications of TCMs in realistic scenarios.

In the previous paper I \cite{bhagwat20} we have shown that self-consistent Extended Thomas-Fermi (ETF) potentials and densities associated with a given finite-range interaction can be parametrized by generalized Fermi distributions. As a next step, a comprehensive calculation of ground-state properties of a large number of spherical and deformed even-even nuclei is carried out in the present work using the Gogny D1S force within the ETF scheme. The parametrized ETF potentials and densities of paper I are used to calculate the smooth part of the energy and the shell corrections within the Wigner-Kirkwood semiclassical averaging scheme. It is shown that the shell corrections thus obtained, along with a simple liquid drop prescription, yield a good description of ground-state masses and potential energy surfaces for nuclei spanning the entire periodic table., Comment: 17 pages, 8 Figures and 2 Tables

We study the $\ensuremath{\alpha}$-decay energies (${Q}_{\ensuremath{\alpha}}$) taken from the Atomic Mass Evaluation 2016 within the valence correlation scheme (VCS). A linear trajectory of $\ensuremath{\alpha}$-decay energies, derived from the VCS for nucleon separation energies, is put forward in terms of $\ifmmode\pm\else\textpm\fi{}\ensuremath{\alpha}{N}_{\mathrm{p}}\ensuremath{\mp}\ensuremath{\beta}{N}_{\mathrm{n}}({N}_{\mathrm{p}}$ and ${N}_{\mathrm{n}}$ are the valence proton and neutron numbers, respectively, counted as particles or holes from the nearest shell closure). It is applicable well to all available $\ensuremath{\alpha}$ emitters including even-even, odd-$A$, and odd-odd nuclei. This relationship can be understood via the Taylor expansion method based on the Bethe-Weizs\"acker (BW) mass formula, leading to the recognition on the origin of the $\ensuremath{\alpha}$-decay energy to some extent as well. In fact, the present study can not only reconfirm the similar linear dependence of nucleon separation energies in the VCS, but also exhibit a regular pattern of $\ensuremath{\alpha}$-decay energy and provide a reasonable estimation on unknown ${Q}_{\ensuremath{\alpha}}$ values.

Second-order topological insulator (SOTI) is featured with the presence of $(d\ensuremath{-}2)$-dimensional boundary states in $d$-dimension systems. The non-Hermiticity induced breakdown of bulk-boundary correspondence (BBC) and the periodic driving on systems generally obscure the description of non-Hermitian SOTI. To prompt the applications of SOTIs, we explore the role of periodic driving in controllably creating exotic non-Hermitian SOTIs both for 2D and 3D systems. A scheme to retrieve the BBC and a complete description to SOTIs via the bulk topology of such nonequilibrium systems are proposed. It is found that rich exotic non-Hermitian SOTIs with a widely tunable number of 2D corner states and 3D hinge states and a coexistence of the first- and second-order topological insulators are induced by the periodic driving. Enriching the family of topological phases, our result may inspire the exploration to apply SOTIs via tuning the number of corner/hinge states by the periodic driving.

We show how the renormalization constant of the Higgs vacuum expectation value, fixed by a tadpole condition, is responsible for gauge dependences in various definitions of parameters in the $R_{\xi}$-gauge. Then we show the relationship of this renormalization constant to the Fleischer-Jegerlehner (FJ) scheme, which is used to avoid these gauge dependences. In this way, we also present a viewpoint on the FJ-scheme complementary to the ones already existing in the literature. Additionally, we compare and discuss different approaches to the renormalization of tadpoles by identifying the similarities and relations between them. The relationship to the Higgs background field renormalization is also discussed., Comment: 16 pages; accepted for publication in prd

Different decompositions (sum rules) for the proton mass have been proposed in the literature. All of them are related to the energy-momentum tensor in quantum chromodynamics. We review and revisit these decompositions by paying special attention to recent developments with regard to the renormalization of the energy-momentum tensor. The connection between the sum rules is discussed as well. We present numerical results for the various terms of the mass decompositions up to 3 loops in the strong coupling, and consider their scheme dependence. We also elaborate on the role played by the trace anomaly and the sigma terms., 28 pages; V2: some discussion added, matches PRD version

We develop, after Dellar (P. J. Dellar, Phys. Rev. E. 65, 036309 (2002), J. Comput. Phys. 190, pp351 (2003)), a multiple-relaxation time (MRT), chromodynamic, multi-component lattice Boltzmann equation (MCLBE) scheme for simulation of isothermal, immiscible fluid flow with a density contrast. It is based on Lishchuk's method (J. U. Brackbill, D. B. Kothe and C. Zemach, J. Comp. Phys. 100, 335-354 (1992), S. V. Lishchuk, C. M. Care and I. Halliday, Phys. Rev. E. 67(3), 036701(2), (2003)) and the segregation of d'Ortona et al. (U. D'Ortona, D. Salin, M. Cieplak, R. B. Rybka and J. R. Banavar Phys. Rev. E. 51, 3718, (1995)). We focus on fundamental model verifiability but do relate some of our data to that from previous approaches, due to Ba et al. (Y. Ba, H. Liu, Q. Li, Q. Kang and J. Sun, Phys. Rev. E 94, 023310 (2016)) and earlier Liu et al. (H. Liu, A. J. Valocchi and Q. Kang, Phys. Rev. E 85, 046309 (2012)), who pioneered large density difference chromodynamic MCLBE and showed the practical benefits of a MRT collision model. Specifically, we test the extent to which chromodynamic MCLBE MRT schemes comply with the kinematic condition of mutual impenetrability and the continuous traction condition by developing analytical benchmarking flows. We conclude that our data, taken with those of Ba et al., verify the utility of MRT chromodynamic MCLBE., submitted to PRE

This paper proposes a recursive protocol that infers the topological information of band degeneracies crossing high-symmetry lines by just calculating the symmetry data at several high-symmetry momenta, instead of a heavy numerical calculation. Two materials are used for the demonstration of the recursive algorithm, one is In2Te having ideal Weyl phonons and the other is ZrSiO having node-cage phonons

We develop a 16-band $\mathbf{k}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbf{p}$ model for the description of wurtzite GaAs, together with a scheme to determine electronic structure parameters for multiband $\mathbf{k}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbf{p}$ models. Our approach uses low-discrepancy sequences to fit $\mathbf{k}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbf{p}$ band structures beyond the eight-band scheme to most recent ab initio data, obtained within the framework for hybrid-functional density functional theory with a screened-exchange hybrid functional. We report structural parameters, elastic constants, band structures along high-symmetry lines, and deformation potentials at the $\mathrm{\ensuremath{\Gamma}}$ point. Based on this, we compute the bulk electronic properties ($\mathrm{\ensuremath{\Gamma}}$ point energies, effective masses, Luttinger-like parameters, and optical matrix parameters) for a ten-band and a sixteen-band $\mathbf{k}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbf{p}$ model for wurtzite GaAs. Our fitting scheme can assign priorities to both selected bands and $\mathbf{k}$ points that are of particular interest for specific applications. Finally, ellipticity conditions can be taken into account within our fitting scheme in order to make the resulting parameter sets robust against spurious solutions.

An experimental scheme is proposed for building massively multipartite entangled states using both the spatial and the frequency modes of an optical parametric oscillator. We provide analytical forms of the entangled states using the squeezed eigenmodes of Heisenberg equations, a.k.a. the nullifiers of the corresponding graph state. This scheme can generate, in parallel, several cluster states described by sparsely connected, bicolorable graph states, usable for one-way quantum computing. We indicate the experimentally accessible quantum graphs, depending on the squeezing parameter.

The construction and classification of symmetry-protected topological (SPT) phases in interacting bosonic and fermionic systems have been intensively studied in the past few years. Very recently, a complete classification and construction of space-group SPT phases were also proposed for interacting bosonic systems. In this Rapid Communication, we attempt to generalize this classification and construction scheme systematically into interacting fermion systems. In particular, we construct and classify point-group SPT phases for two-dimensional (2D) interacting fermion systems via lower-dimensional block-state decorations. We discover several intriguing fermionic SPT states that can only be realized in interacting fermion systems (i.e., not in free-fermion or bosonic SPT systems). Moreover, we also verify the recently conjectured crystalline equivalence principle for 2D interacting fermion systems. Finally, the potential experimental realization of these different classes of point-group SPT phases in 2D correlated superconductors is addressed.

In the recent CODATA-2014 adjustment, the $G$ values obtained by different groups are not in good agreement with each other within respective uncertainties, which may be attributed to the possible unknown or incorrectly evaluated systematic errors in different methods. This paper proposes a scheme to measure $G$ with two independent methods. The first method is the extraction of the $G$ value from the fundamental periods of the torsion pendulum, with the source masses at two positions; the other one determines the $G$ value on the basis of the amplitude of the third-order harmonic component of the torsion pendulum. Both methods are performed with the same setup by using the large-amplitude torsion pendulum. Through theoretical derivation and simulation, the uncertainties of the $G$ values obtained by the two methods are both expected to be within 20 ppm. By comparing the $G$ values from the two methods, we can explore the potential systematic errors in the measurement.

The study of gapped quantum many-body systems in three spatial dimensions has uncovered the existence of quantum states hosting quasiparticles that are confined, not by energetics but by the structure of local operators, to move along lower dimensional submanifolds. These so-called "fracton" phases are beyond the usual topological quantum field theory description, and thus require new theoretical frameworks to describe them. Here we consider coupling fracton models to topological quantum field theories in (3+1) dimensions by starting with two copies of a known fracton model and gauging the $\mathbb{Z}_2$ symmetry that exchanges the two copies. This yields a class of exactly solvable lattice models that we study in detail for the case of the X-cube model and Haah's cubic code. The resulting phases host finite-energy non-Abelian immobile quasiparticles with robust degeneracies that depend on their relative positions. The phases also host non-Abelian string excitations with robust degeneracies that depend on the string geometry. Applying the construction to Haah's cubic code in particular provides an exactly solvable model with finite energy yet immobile non-Abelian quasiparticles that can only be created at the corners of operators with fractal support., 29+9 pages, 28+5 figures

The level scheme of the compound $^{153}\mathrm{Sm}$ nucleus formed via the $^{152}\mathrm{Sm}({n}_{\text{th}},\ensuremath{\gamma})$ reaction is studied by using a $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ coincidence spectrometer at Dalat Nuclear Research Institute, Vietnam. All the $\ensuremath{\gamma}$ cascades, which correspond to the decays from the compound state to 12 final levels of 0 (${\frac{3}{2}}^{+}$), 7.535 (${\frac{5}{2}}^{+}$), 35.844 (${\frac{3}{2}}^{\ensuremath{-}}$), 90.875 (${\frac{5}{2}}^{\ensuremath{-}}$), 126.412 (${\frac{1}{2}}^{\ensuremath{-}}$), 127.298 (${\frac{3}{2}}^{\ensuremath{-}}$), 182.902 (${\frac{5}{2}}^{\ensuremath{-}}$), 321.113 (${\frac{3}{2}}^{+}$), 404.129 (${\frac{1}{2}}^{\ensuremath{-}}$), 405.470 (${\frac{3}{2}}^{\ensuremath{-}}$), 414.924 (${\frac{1}{2}}^{+}$), and 481.088 (${\frac{3}{2}}^{+}$) keV, have been measured. A total number of 386 cascades corresponding to 576 $\ensuremath{\gamma}$ transitions has been detected. Among these cascades, 103 primary $\ensuremath{\gamma}$ transitions together with their corresponding intermediate levels and 299 secondary transitions have been determined. In addition, 29 primary $\ensuremath{\gamma}$ transitions, 42 intermediate levels, and 8 secondary transitions have been found to be the same as those extracted from the Evaluated Nuclear Structure Data File (ENSDF) data. The remaining 74 primary $\ensuremath{\gamma}$ transitions, 61 intermediate levels, and 291 secondary transitions are therefore considered as new data. In particular, based on an assumption that most of the transitions are dipole, we have tentatively assigned the unique spin value of $\frac{3}{2}\ensuremath{\hbar}$ for 53 observed intermediate levels corresponding to the cascades from the compound state to the final levels of 7.535 (${\frac{5}{2}}^{+}$), 90.875 (${\frac{5}{2}}^{\ensuremath{-}}$), and 182.902 (${\frac{5}{2}}^{\ensuremath{-}}$) keV, whereas the remaining levels are assigned with the spin values in the range of $[\frac{1}{2},\frac{3}{2}]\ensuremath{\hbar}$. Moreover, the total and partial (for the spin range of $[\frac{1}{2},\frac{3}{2}]\ensuremath{\hbar}$) cumulative numbers of levels have been constructed by combining the ENSDF data with the new data obtained in the present experiment. Comparison between these new cumulative curves and those extracted from the nuclear level density (NLD) data, which are obtained using the Oslo method, shows that the maximum excitation energy ${E}_{\mathrm{max}}$, defined as the energy threshold below which most of the excited levels are observed, is extended to about 1.2 and 1.8 MeV for the total and partial NLD data, respectively. These values of ${E}_{\mathrm{max}}$ are higher than those obtained by using the present ENSDF data, which are around 1 MeV. The new cumulative curves have also been compared with different phenomenological and microscopic NLD models, and the recent exact pairing plus independent-particle model at finite temperature ($\mathrm{EP}+\mathrm{IPM}$), in which no fitting parameter has been employed, is found to be the best-fit one. The present findings provide updated information on the nuclear level structure and make a step toward the completed level schemes of excited compound nuclei.

Discretizing transverse linear momentum of photon pairs, generated by spontaneous parametric down conversion (SPDC), is one of the simplest methods for producing bipartite entangled states in high dimensions. So far, it has been employed only to prepare states in dimensions $m\ifmmode\times\else\texttimes\fi{}m$. In this work, we study the generalization for engineering entangled states in dimensions $m\ifmmode\times\else\texttimes\fi{}n$. Our approach relies on the manipulation of the pump beam transverse profile and the phase-matching function of the SPDC process to prepare, behind an $m$- and $n$-slit aperture, different $m\ifmmode\times\else\texttimes\fi{}n$ spatial entangled states. We demonstrate the technique experimentally for some $2\ifmmode\times\else\texttimes\fi{}3$ states. Compared to previous approaches in producing $2\ifmmode\times\else\texttimes\fi{}n$ photonic entanglement, which require either more than two photons or hybrid entanglement, our scheme is less demanding and simpler since we employ only two photons and a single degree of freedom to encode the states.

We discuss the fact that $k_t$-factorization calculations for heavy-quark production include only the $gg\rightarrow Q\bar{Q}$ contribution. The cases of fixed-flavor-number scheme and variable-flavor-number scheme calculations are analyzed separately. For the latter, we show that, similarly to the collinear factorization, the main contribution is given by the $Qg\rightarrow Qg$ process. In this scheme, calculations including only the $gg$ contribution should show a large discrepancy with the data. We show that, if they do not, it is because they include (effectively) a large $K$ factor., Comment: Important modifications, new figures are added. Published in Phys. Rev. D 99, 074006 (2019)

The seniority symmetry is known to be partially conserved in two special cases in the ${(9/2)}^{4}$ system, which can lead to striking features in the corresponding structure and electromagnetic transition properties. However, it is still quite difficult to derive those kind of solvable states, in general, especially towards higher-$j$ orbits. We have developed a novel and effective way to confront this challenge by starting from the $m$ scheme and making use of the angular momentum projection method. It also allows us to explore another special family of seniority conserving states in the midshell besides the specific case of the ${(9/2)}^{4}$ configuration. Moreover, we have studied systemically all states in single-$j$ systems up to $j=15/2$ and derived the analytic expressions for the eigenvalues of all solvable states with a focus on those in $j=9/2$ and $j=11/2$. Such studies can also be useful for the experimental search of relevant states and for the understanding of their electromagnetic transition properties.

We study a gauged $CP(2)$ model with the Chern-Simons term, focusing our attention on those time-independent radially symmetric configurations with a nontopological profile. We proceed with the minimization of the effective energy in order to introduce the corresponding first-order framework, from which we define a legitimate self-dual scenario. We solve the resulting first-order equations numerically by means of the finite-difference scheme, from which we depict the nontopological solutions. We also identify a special kind of solution which can be partially described by an analytical treatment.

Study of scattering process in the nonlocal interaction framework leads to an integro-differential equation. The purpose of the present work is to develop an efficient approach to solve this integro-differential equation with high degree of precision. The method developed here employs Taylor approximation for the radial wave function which converts the integro-differential equation in to a readily solvable second-order homogeneous differential equation. This scheme is found to be computationally efficient by a factor of 10 when compared to the iterative scheme developed in J.~Phys.~G~Nucl.~Part.~Phys.~{\bf 45},~015106~(2018). The calculated observables for neutron scattering off $^{24}$Mg, $^{40}$Ca, $^{100}$Mo and $^{208}$Pb with energies up to 10 MeV are found to be within at most 8$\%$ of those obtained with the iterative scheme. Further, we propose an improvement over the Taylor scheme that brings the observables so close to the results obtained by iterative scheme that they are visually indistinguishable. This is achieved without any appreciable change in the run time., 9 pages, 9 figures, accepted in Physical Review C

We calculate the wave-function renormalization in 2-dimensional O(3) sigma model, non- perturbatively. It is evaluated in a box with a finite spatial extent. We determine the anomalous dimension in the finite volume scheme through an analysis of the step scaling function. Results are compared with a perturbative evaluation, and the reasonable behavior is confirmed.

We investigate the regularization-scheme dependent treatment of γ5 in the framework of dimensional regularization, mainly focusing on the four-dimensional helicity scheme (fdh). Evaluating distinctive examples, we find that for one-loop calculations, the recently proposed four-dimensional formulation (fdf) of the fdh scheme constitutes a viable and efficient alternative compared to more traditional approaches. In addition, we extend the considerations to the two-loop level and compute the pseudoscalar form factors of quarks and gluons in fdh. We provide the necessary operator renormalization and discuss at a practical level how the complexity of intermediate calculational steps can be reduced in an efficient way.

The Luttinger-Ward functional (LWF) has been a starting point for conserving approximations in many-body physics for 50 years. The recent discoveries of its multivaluedness and the associated divergence of the two-particle irreducible vertex function $\Gamma$ have revealed an inherent limitation of this approach. Here we demonstrate how these undesirable properties of the LWF can lead to a failure of computational methods based on an approximation of the LWF. We apply the Nested Cluster Scheme (NCS) to the Hubbard model and observe the existence of an additional stationary point of the self-consistent equations, associated with an unphysical branch of the LWF. In the strongly correlated regime, starting with the first divergence of $\Gamma$, this unphysical stationary point becomes attractive in the standard iterative technique used to solve DMFT. This leads to an incorrect solution, even in the large cluster size limit, for which we discuss diagnostics., Comment: 28 pages, 22 figures, v3 PRB structure, and minor corrections

We consider a gauged $CP(2)$ theory in the presence of the Chern-Simons action, focusing our attention on those time-independent solutions possessing radial symmetry. In this context, we develop a coherent first-order framework via the Bogomol'nyi prescription, from which we obtain the corresponding energy lower-bound and the first-order equations the model supports. We use these expressions to introduce effective BPS scenarios, solving the resulting first-order equations by means of the finite-difference scheme, this way attaining genuine field solutions engendering topological configurations. We depict the new profiles, commenting on the main properties they engender.

We study theoretically a weak measurement of an observable $A$ and its impact on a subsequent strong measurement of another observable $B$. We assume that both measurements are described by the Gaussian point detectors. It is shown that a decrease of the system-detector interaction during the measurement of $A$ results in an increase of the fluctuations of $A$, while the mean value of $A$ is kept unaltered. The ratio ${(\mathrm{\ensuremath{\Delta}}A)}_{\mathrm{weak}\phantom{\rule{0.28em}{0ex}}\phantom{\rule{0.16em}{0ex}}\mathrm{measurement}}/{(\mathrm{\ensuremath{\Delta}}A)}_{\mathrm{strong}\phantom{\rule{0.28em}{0ex}}\phantom{\rule{0.16em}{0ex}}\mathrm{measurement}}$ turns out to be universal, i.e., independent of the physical system, its quantum state, and the quantity measured. Most of our attention is focused on analyzing outcomes of the subsequent strong measurement of the quantity $B$, namely, on the mean value $\overline{B}$ and the variance ${(\mathrm{\ensuremath{\Delta}}B)}^{2}$. We derive explicit analytic corrections for $\overline{B}$ and ${(\mathrm{\ensuremath{\Delta}}B)}^{2}$ arising due to the prior weak measurement of $A$. Importantly, the leading-order impact of the weak measurement of $A$ on $\overline{B}$ and ${(\mathrm{\ensuremath{\Delta}}B)}^{2}$ is encoded in the terms ${\phantom{\rule{0.16em}{0ex}}}_{s}\ensuremath{\langle}\ensuremath{\psi}|[\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{A},[\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{A},{\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{B}}^{k}]]{|\ensuremath{\psi}\ensuremath{\rangle}}_{s}$, where $k=1,2$ and ${|\ensuremath{\psi}\ensuremath{\rangle}}_{s}$ is the quantum state vector of our system before the measurements. Our additional contribution consists of deriving Heisenberg-like uncertainty relations for the product ${(\mathrm{\ensuremath{\Delta}}A)}_{\mathrm{weak}\phantom{\rule{0.28em}{0ex}}\phantom{\rule{0.16em}{0ex}}\mathrm{measurement}}\phantom{\rule{0.28em}{0ex}}{(\mathrm{\ensuremath{\Delta}}B)}_{\mathrm{strong}\phantom{\rule{0.28em}{0ex}}\phantom{\rule{0.16em}{0ex}}\mathrm{measurement}}$ and analyzing the case of minimum uncertainty. Finally, our theoretical developments are illustrated numerically via studying the $s$ states of the hydrogen atom, assuming $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{A}=\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{r}$ (atomic radius) and $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{B}=\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{H}$ (energy).

Recently, I proposed a fast computing scheme for generalized seniority on a spherical single-particle basis [J. Phys. G: Nucl. Part. Phys. 42, 115105 (2015)]. This work redesigns the scheme to make it applicable to deformed single-particle basis. The algorithm is applied to the rare-earth-metal nucleus $_{64}^{158}\mathrm{Gd}_{94}$ for intrinsic (body-fixed frame) neutron excitations under the low-momentum NN interaction ${V}_{\mathrm{low}\text{\ensuremath{-}}k}$. By allowing as many as four broken pairs, I compute the lowest 300 intrinsic states of several multipolarities. These states converge well to the exact ones, showing generalized seniority is very effective in truncating the deformed shell model. Under realistic interactions, the picture remains approximately valid: The ground state is a coherent pair condensate and the pairs gradually break up as excitation energy increases.

We present a correction scheme for periodic $\mathrm{\ensuremath{\Gamma}}$-only $GW$ calculations in a Gaussian basis. For four benchmark systems, the dependence of the corrected $GW$ quasiparticle levels on the cell size is reduced by a factor of three to ten compared to $GW$ calculations without correction. The correction scheme comes along with negligible computational cost and enables $GW$ calculations for supercells containing hundreds of atoms with Gaussian basis functions.

We examine the possibility of travelling wave solutions within the nonlinear Euler-Heisenberg electrodynamics. Since this theory resembles in its form the electrodynamics in matter, it is a priori not clear if there exist travelling wave solutions with a new dispersion relation for $\omega(k)$ or if the Euler-Heisenberg theory stringently imposes $\omega=k$ for any arbitrary ansatz $\mathbf{E}(\xi)$ and $\mathbf{B}(\xi)$ with $\xi \equiv \mathbf{k}\cdot\mathbf{r} -\omega t$. We show that the latter scheme applies for the Euler-Heisenberg theory, but point out the possibility of new solutions with $\omega \neq k$ if we go beyond the Euler-Heisenberg theory, allowing strong fields. In case of the Euler-Heisenberg theory the quantum mechanical effect of the travelling wave solutions remains in $\hbar$ corrections to the energy density and the Poynting vector., Comment: 26 pages

We analyze a similar scheme for producing light-mediated entanglement between atomic ensembles, as first realized by Julsgaard, Kozhekin, and Polzik [Nature (London) 413, 400 (2001)]. In the standa ...

In this paper we show that $ip\ensuremath{-}jn$ relations for nuclear masses and charge radii of four neighboring nuclei reconcile with Casten's ${N}_{p}{N}_{n}$ scheme.

In this work we outline a simple and numerically inexpensive approach to describe the spectral features of the single-impurity Anderson model. The method combines aspects of the density matrix embedding theory (DMET) approach with a spectral broadening approach inspired by those used in numerical renormalization group (NRG) methods. At zero temperature for a wide range of U , the spectral function produced by this approach is found to be in good agreement with general expectations as well as more advanced and complex numerical methods such as DMRG-based schemes. The theory developed here is simply transferable to more complex impurity problems., 8 pages, 9 figures; Results unchanged

Using coherent states in optical quantum process tomography is a practically-relevant approach. Here, we develop a framework for complete characterization of quantum-optical processes in terms of normally-ordered moments by using coherent states as probes. We derive the associated superoperator tensors for several optical processes. We also show that our technique can be used to determine nonclassicality features of quantum-optical states and processes. Furthermore, we investigate identification of multi-mode Gaussian processes and show that the number of necessary probe coherent states scales linearly with the number of modes.

International audience; Within the framework of the central-moment-based lattice Boltzmann method, we propose a strategy to account for external forces in two and three dimensions. Its numerical properties are evaluated against consolidated nbenchmark problems, highlighting very high accuracy and optimal convergence. Moreover, our derivations are light and intelligible.

Antiferromagnetic molecular rings are widely studied both for fundamental quantum-mechanical issues and for technological applications, particularly in the field of quantum information processing. Here we present a detailed first-principles study of two families---purple and green---of ${{\mathrm{Cr}}_{7}M}$ antiferromagnetic rings, where $M$ is a divalent transition metal ion ($M={\mathrm{Ni}}^{2+}, {\mathrm{Mn}}^{2+}$, and ${\mathrm{Zn}}^{2+}$). We employ a recently developed flexible and efficient scheme to build ab initio system-specific Hubbard models. From such many-body models we systematically derive the low-energy effective spin Hamiltonian for the rings. Our approach allows us to calculate isotropic as well as anisotropic terms of the spin Hamiltonian, without any a priori assumption on its form. For each compound we calculate magnetic exchange couplings, zero-field splitting tensors, and gyromagnetic tensors, finding good agreement with experimental results.

By using the general triaxial rotor model (TRM) and the phonon-configuration mixing scheme within an anharmonic-vibrator (AHV) framework, a series of global correlations between electromagnetic properties of nuclear ${2}_{1}^{+}$ and ${2}_{2}^{+}$ states are analytically established. The correlations from both models can roughly describe the experimental data involving quadrupole collectivity with few exceptions. Furthermore, there seems to be a robust orthogonal transformation between the AHV and the TRM bases for realistic nuclear systems, suggesting that the two models may in fact be describing the collective features of nuclear low-lying states in similar model spaces.