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In quantum mechanics, joint measurements of non-commuting observables are only possible if a minimal unavoidable measurement uncertainty is accepted. On the other hand, correlations between non-commuting observables can exceed classical limits, as demonstrated by the violation of Bell's inequalities. Here, the relation between the uncertainty limited statistics of joint measurements and the limits on expectation values of possible input states is analyzed. It is shown that the experimentally observable statistics of joint measurements explain the uncertainty limits of local states, but result in less restrictive bounds when applied to identify the limits of non-local correlations between two separate quantum systems. A tight upper bound is obtained for the four correlations that appear in the violation of Bell's inequalities and the statistics of pure states saturating the bound is characterized. The results indicate that the limitations of quantum non-locality are a necessary consequence of the local features of joint measurements, suggesting the possibility that quantum non-locality could be explained in terms of the local characteristics of quantum statistics., Comment: 10 pages, no figures, added explanation of joint and sequential measurements and corrections in the references

We study suspensions of rigid particles in a plane Couette flow with deformable elastic walls. We find that, in the limit of vanishing inertia, the elastic walls induce shear thinning of the suspen ...

Reaching a target quantum state from an initial state within a finite temporal window is a challenging problem due to nonadiabaticity. We study the optimal protocol for switching on interactions to reach the ground state of a weakly interacting Luttinger liquid within a finite time $\ensuremath{\tau}$, starting from the noninteracting ground state. The protocol is optimized by minimizing the excess energy at the end of the quench, or by maximizing the overlap with the interacting ground state. We find that the optimal protocol is symmetric with respect to $\ensuremath{\tau}/2$, and can be expressed as a functional of the occupation numbers of the bosonic modes in the final state. For short quench durations, the optimal protocol exhibits fast oscillation and excites high-energy modes. In the limit of large $\ensuremath{\tau}$, minimizing energy requires a smooth protocol while maximizing overlap requires a linear quench protocol. In this limit, the minimal energy and maximal overlap are both universal functions of the system size and the duration of the protocol.

We discuss real time evolution for the quantum Ising model in one spatial dimension with $N_s$ sites. In the limit where the nearest neighbor interactions $J$ in the spatial directions are small, there is a simple physical picture where qubit states can be interpreted as approximate particle occupations. Using exact diagonalization, for initial states with one or two particles, we show that for small $J$, discrete Bessel functions provide very accurate expressions for the evolution of the occupancies corresponding to initial states with one and two particles. Boundary conditions play an important role when the evolution time is long enough. We discuss a Trotter procedure to implement the evolution on existing quantum computers and discuss the error associated with the Trotter step size. We discuss the effects of gate and measurement errors on the evolution of one and two particle states using 4 and 8 qubits circuits approximately corresponding to existing or near term quantum computers., 13 pages, 12 figures

We investigate the linear regime of $f(R)=R+\ensuremath{\alpha}{R}^{2}$ gravity for static, spherically symmetric and asymptotically flat configurations of matter. We show that, in vacuum and deep inside the range of the extra scalar degree of freedom, the post-Newtonian parameter $\ensuremath{\gamma}$ is not equal to $1/2$, as established in the literature, but it assumes larger values depending on the pressure of the star. We provide an explicit expression for $\ensuremath{\gamma}$ in terms of the mass, of the integrated pressure of the star and of the ratio between the star's radius and the range of the extra degree of freedom. We corroborate our results by providing numerical solutions for the case of a neutron star.

We provide exact results for the mean and variance of first-passage times (FPTs) of making a directed revolution in the presence of a bias in heterogeneous quenched environments where the disorder is expressed by random traps on a ring with period $L$. FPT statistics are crucially affected by the disorder realization. In the large-$L$ limit, we obtain exact formulae for the FPT statistics, which are described by the sample mean and variance for waiting times of periodically arranged traps. Furthermore, we find that these formulae are still useful for nonperiodic heterogeneous environments; i.e, the results are valid for almost all disorder realizations. Our findings are fundamentally important for the application of FPT to estimate diffusivity of a heterogeneous environment under a bias., Comment: 10 pages, 5 figures

In this paper, we study inflation in the $\ensuremath{\alpha}$-attractor framework with an exponential potential in the Randall-Sundrum (RS) braneworlds, where high-energy corrections to the Friedmann equation facilitate a slow roll. In this scenario, we numerically investigate the inflationary parameters and show that the high-energy brane corrections have a significant effect on the parameter $\ensuremath{\alpha}$; namely, the lower values of the parameter are preferred by observation in this limit. The latter substantially reduces the tensor-to-scalar ratio of perturbations, making the RS braneworld inflation compatible with observation. We also point out that sub-Planckian values of the field displacement can be achieved by suitably constraining the brane tension.

We study the quantum Zeno effect of the circuit-QED system at finite temperature for both selective measurement and nonselective measurement proposals. For the selective measurement proposal, we explicitly show that the counter-rotating terms (CRTs) become as significant as rotating wave terms (RWTs) with increase of temperature. We also derive an analytic expression for the survival probability which correctly captures the leading contribution for both RWTs and CRTs in the frequent measurement limit. Beyond this limit, we observe a nonexponential decay of the survival probability by further considering the effect of the variation of initial states during repeated measurements. For the nonselective measurement proposal, we find that the survival probability demonstrates the same behavior as in the selective measurement case in the short-time regime while it deviates from an exponential form and approaches a nonvanishing value in the long-time scale due to the repopulation effect.

Simple analytic formulas are considered for the energy radiated in low frequency bremsstrahlung from fully ionized gases. A formula that has been frequently cited over many years turns out to have only a limited range of validity, more narrow than for a formula derived using the Born approximation. In an attempt to find a more widely valid simple formula, a soft photon theorem is employed, which in this context implies that the differential rate of photon emission in an electron-ion collision with definite initial and final electron momenta is correctly given for sufficiently soft photons by the Born approximation, to all orders in the Coulomb potential. Corrections to the Born approximation arise because the upper limit on photon energy for this theorem to apply to a given collision becomes increasingly stringent as the scattering approaches the forward direction. A general formula is suggested that takes this into account., Comment: 14 pages, no figures

Minute changes in the composition of complex metal-oxide films strongly affect their physical properties, and, in turn, their functionality in novel thin-film devices. The authors combine atomically resolved scanning tunneling microscopy with pulsed laser deposition, and devise a novel method that measures the composition of the deposited material with a precision that is far beyond current analysis techniques: By quantitatively evaluating the surface structures of SrTiO${}_{3}$(110), and exploiting their exquisite sensitivity to surface stoichiometry changes, they can determine the composition of the material with a sensitivity of 0.1%, at least ten times better than other customary techniques.

Computing momentum-dependent susceptibilities in the dynamical mean-field theory (DMFT) requires solving the Bethe-Salpeter equation, which demands large computational cost. Exploiting the strong-coupling feature of local fluctuations, we derive a simplified formula that can be solved at a considerably lower cost. The validity and the physical meaning of the formula are confirmed by deriving the effective intersite interactions in the strong-coupling limit, such as the kinetic exchange and RKKY interactions. Furthermore, numerical calculations for single-orbital and multiorbital models demonstrate surprisingly wider applicability including weak-coupling region. Based on this formula, we propose three levels of practical approximations that can be chosen depending on complexity of problems. Simpler evaluations of spin and orbital susceptibilities in multiorbital systems thus become possible within DMFT., Comment: 18 pages, 20 figures

A quantum error correction (QEC) code uses $N_{\rm c}$ quantum bits to construct one "logical" quantum bits of better quality than the original "physical" ones. QEC theory predicts that the failure probability $p_L$ of logical qubits decreases exponentially with $N_{\rm c}$ provided the failure probability $p$ of the physical qubit is below a certain threshold $p, Comment: Published version. New discussion added at the end

We formally extend the notion of Markov order to open quantum processes by accounting for the instruments used to probe the system of interest at different times. Our description recovers the classical Markov order property in the appropriate limit: when the stochastic process is classical and the instruments are non-invasive, \emph{i.e.}, restricted to orthogonal, projective measurements. We then prove that there do not exist non-Markovian quantum processes that have finite Markov order with respect to all possible instruments; the same process exhibits distinct memory effects with respect to different probing instruments. This naturally leads to a relaxed definition of quantum Markov order with respect to specified sequences of instruments. The memory effects captured by different choices of instruments vary dramatically, providing a rich landscape for future exploration., Comment: 4.5+2 pages, 3 figures

In this paper, we study the pseudo-Wigner solution of the quark gap equation with a recently proposed algorithm in the framework of the ($2+1$)-flavor Nambu-Jona-Lasinio (NJL) model. We find that for the current quark mass ${m}_{u,d}=5.5\text{ }\text{ }\mathrm{MeV}$ and chemical potential $\ensuremath{\mu}l{\ensuremath{\mu}}_{\mathrm{TCP}}=272.5\text{ }\text{ }\mathrm{MeV}$, the Nambu solution and the positive pseudo-Wigner solution obtained via this algorithm is consistent with the physical solution obtained with the iterative method. Furthermore, the algorithm we used can help to illustrate the evolution of the solutions of the gap equation from the chiral limit to nonchiral limit and gives a prediction where the crossover line is located in the phase diagram for $\ensuremath{\mu}l272.5\text{ }\text{ }\mathrm{MeV}$. In addition, we also study the chiral susceptibilities as well as the loss of solutions for different chemical potentials.

We consider the derivation and numerical solution of the flow of passive and active polar liquid crystals, whose molecular orientation is subjected to a tangential anchoring on an evolving curved surface. The underlying passive model is a simplified surface Ericksen-Leslie model, which is derived as a thin-film limit of the corresponding three-dimensional equations with appropriate boundary conditions. A finite element discretization is considered and the effect of hydrodynamics on the interplay of topology, geometric properties and defect dynamics is studied for this model on various stationary and evolving surfaces. Additionally, we consider an active model. We propose a surface formulation for an active polar viscous gel and exemplarily demonstrate the effect of the underlying curvature on the location of topological defects on a torus.

We study random sequential adsorption of particles from pool onto a one dimensional substrate following ballistic deposition rules, with separate nucleation and growth processes occurring simultaneously. Nucleation describes the formation of point-sized seeds, and after a seed is sown, it acts as an attractor and grows in size by the addition of grains of a fixed-sized. At each time step either an already-nucleated seed can increase in size, or a new seed may be nucleated. We incorporate a parameter $m$, to describe the relative rates of growth to nucleation. We solve the model analytically to obtain gap size distribution function and a general expression for the jamming coverage as a function of $m$. We show that the jamming coverage $\theta(m)$ reaches its maximum value $\theta(m)=1$ in the limit $m\rightarrow \infty$ following a power-law $\theta(\infty) - \theta(m) \sim m^{-1/2}$. We also perform extensive Monte Carlo simulation and find excellent agreement between analytic and numerical results., Comment: 8 pages, 5 captioned figures

We develop an analytical framework to study the synchronization of a quantum self-sustained oscillator to an external signal. Our unified description allows us to identify the resource on which quantum synchronization relies, and to compare quantitatively the synchronization behavior of different limit cycles and signals. We focus on the most elementary quantum system that is able to host a self-sustained oscillation, namely a single spin 1. Despite the spin having no classical analogue, we first show that it can realize the van der Pol limit cycle deep in the quantum regime, which allows us to provide an analytical understanding to recently reported numerical results. Moving on to the equatorial limit cycle, we then reveal the existence of an interference-based quantum synchronization blockade and extend the classical Arnold tongue to a snake-like split tongue. Finally, we derive the maximum synchronization that can be achieved in the spin-1 system, and construct a limit cycle that reaches this fundamental limit asymptotically., 15 pages, 9 figures, equivalent to published version

We study the many-body dynamics of stimulated Raman adiabatic passage in the presence of on-site interactions. In the classical mean-field limit, explored in Phys. Rev. Lett. {\bf 121}, 250405 (2018), interaction-induced chaos leads to the breakdown of adiabaticity under the quasi-static variation of the parameters, thus producing {\em low} sweep rate boundaries on efficient population transfer. We show that for the corresponding many-body system, alternative quantum pathways from the initial to the target state, open up at even slower sweep rates. These quantum detours avoid the chaotic classical path and hence allow a robust and efficient population transfer., 11 pages, 17 figures

A powerful historical insight about the theory of in-medium showering in QCD backgrounds was that splitting rates can be related to a parameter $\hat q$ that characterizes the rate of transverse-momentum kicks to a high-energy particle from the medium. Another powerful insight was that $\hat q$ can be defined (with caveats) even when the medium is strongly coupled, using long, narrow Wilson loops whose two long edges are light-like Wilson lines. The medium effects for the original calculations of in-medium splitting rates can be formulated in terms of 3-body imaginary-valued `potentials' that are defined with three long, light-like Wilson lines. Corrections due to overlap of two consecutive splittings can be calculated using similarly defined 4-body potentials. I give a simple argument for how such $N$-body potentials can be determined in the appropriate limit just from knowledge of the values of $\hat q$ for different color representations. For $N > 3$, the $N$-body potentials have non-trivial color structure, which will complicate calculations of overlap corrections outside of the large-$N_c$ or soft bremsstrahlung limits., 20 pages, 8 figures

We study classical Markovian stochastic systems with discrete states, coupled to randomly switching external environments. For fast environmental processes we derive reduced dynamics for the system itself, focusing on corrections to the adiabatic limit of infinite timescale separation. We show that this can lead to master equations with bursting events. Negative transition rates can result in the reduced master equation, leading to unphysical short-time behavior. However, the reduced master equation can describe stationary states better than a leading-order adiabatic calculation, similar to what is known for Kramers-Moyal expansions in the context of the Pawula theorem [R. F. Pawula, Phys. Rev. 162, 186 (1967)PHRVAO0031-899X10.1103/PhysRev.162.186; H. Risken and H. Vollmer, Z. Phys. B 35, 313 (1979)ZPBBDJ0340-224X10.1007/BF01319854]. We provide an interpretation of the reduced dynamics in discrete time and a criterion for the occurrence of negative rates for systems with two environmental states.

The optical properties of the new iron-based superconductor ${\mathrm{CsCa}}_{2}{\mathrm{Fe}}_{4}{\mathrm{As}}_{4}{\mathrm{F}}_{2}$ with ${T}_{c}\ensuremath{\simeq}29$ K have been determined. In the normal state a good description of the low-frequency response is obtained with a superposition of two Drude components of which one has a very low scattering rate (narrow Drude peak) and the other a rather large one (broad Drude peak). Well below ${T}_{c}\ensuremath{\simeq}29$ K, a pronounced gap feature is observed which involves a complete suppression of the optical conductivity below $\ensuremath{\sim}110\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ and thus is characteristic of a nodeless superconducting state. The optical response of the broad Drude component can be described with a dirty-limit Mattis-Bardeen-type response with a single isotropic gap of $2\mathrm{\ensuremath{\Delta}}\ensuremath{\simeq}14$ meV. To the contrary, the response of the narrow Drude component is in the ultraclean limit and its entire spectral weight is transferred to the zero-frequency $\ensuremath{\delta}(\ensuremath{\omega})$ function that accounts for the loss-free response of the condensate. These observations provide clear evidence for a band-selective coexistence of clean- and dirty-limit superconductivity with nodeless gaps in ${\mathrm{CsCa}}_{2}{\mathrm{Fe}}_{4}{\mathrm{As}}_{4}{\mathrm{F}}_{2}$.

Fil: Willemyns, Cintia Teresita. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina. Comision Nacional de Energia Atomica. Gerencia del Area de Investigaciones y Aplicaciones no Nucleares. Gerencia de Fisica (Centro Atomico Constituyentes); Argentina

A three-dimensional lattice-Boltzmann model (LBM) for the simulation of the Maxwell equations is presented. The inclusion of media follows an extension of a special limit described in the literature which is applicable to this LBM and does not harm the stability of simulations. The focus of the present study lies on the properties of numerical accuracy and stability of the LBM in comparison to the standard finite-difference time-domain (FDTD) method based on Yee's method. Typical examples, often investigated in the context of numerical simulations, are considered. These include the propagation of electrodynamic (EM) fields in one- and three-dimensional systems. Results of this simulations are compared to the ones of their theoretical predictions. Further on, long-time simulations are done in systems with periodic boundary conditions to check if the total energy is conserved. To investigate the effect of the numeric impedance, the propagation of an EM pulse is monitored spatially and temporarily in a two-dimensional system. The simulation results indicate, in contrast to the one obtained from the FDTD method, that the presented LBM does fulfill the expected energy conservation and is not effected by the numerical impedance. This LBM therefore represents a valuable alternative for the simulation of EM problems like long-time simulations by avoiding intrinsic properties the FDTD method suffers from.

We investigate the potential of the Large Hadron Collider (LHC) to probe one of the most compelling beyond the Standard Model frameworks—walking technicolor (WTC), involving strong dynamics and having a slowly running (walking) new strong coupling. For this purpose we use recent LHC Run 2 data to explore the full parameter space of the minimal WTC model using dilepton signatures from heavy neutral Z′ and Z′′ resonances predicted by the model. This signature is the most promising one for discovery of WTC at the LHC for the low-intermediate values of the g˜ coupling—one of the principle parameters of WTC. We have demonstrated complementarity of the dilepton signals from both resonances, established the most up-to-date limit on the WTC parameter space, and provided projections for the LHC potential to probe the WTC parameter space at higher future luminosities and upgraded energy. We have explored the whole four-dimensional parameter space of the model and have found the most conservative limit on the WTC scale MA above 3 TeV for the low values of g˜, which is significantly higher than previous limits established by the LHC collaborations.

With recent advances in dynamic scanning probe microscopy techniques, it is now a routine to image the sub-molecular structure of molecules with atomically-engineered tips which are prepared via controlled modification of the tip termination and are chemically well-defined. The enhanced spatial resolution is possible as atomically-engineered tips can preserve their integrity in the repulsive interaction regime. Although the mechanism of improved spatial resolution has been investigated both experimentally and theoretically, the ultimate temporal resolution while preserving picometer scale spatial resolution still remains an open question. Here, we computationally analyze the temporal resolution of atomic force microscopy imaging with atomically-engineered tips. Our computational results reveal that non-metal terminated tips, e.g. oxygen-terminated copper, are well-suited for enhanced temporal resolution up to video rate imaging velocities while preserving picometer range spatial resolution. Contrarily, the highest-attainable spatial resolution of atomically-engineered tips with low-stiffness, e.g. CO-terminated, deteriorate with increasing imaging velocity. Our results reveal that when atomically-engineered tips terminated with molecules are in use, imaging velocities in the order of nanometers per second at most are inevitable even for atomically flat surfaces to retain atomic resolution and avoid slip-stick motion. In addition to shedding light on the temporal resolution of atomic force microscopy imaging with atomically-engineered tips, our numerical results provide an outlook to the scalability of atom-by-atom fabrication using scanning probe microscopy techniques., 11 pages, 4 figures

A major barrier in the study of neutron-induced nuclear reactions is the impossibility of direct measurements with short-lived radioactive isotopes. For these exotic nuclei, theoretical inputs such as the photon strength function (PSF) are poorly constrained. At Los Alamos National Laboratory, the Detector for Advanced Neutron Capture Experiments (DANCE) provides direct measurements of $\ensuremath{\gamma}$-ray cascades following neutron capture reactions on stable or long-lived radioactive nuclei. While Hauser-Feshbach calculations can provide reasonable predictions for neutron capture on heavy nuclei, their application to neutron-rich light nuclei with low nuclear level densities and low neutron separation energies is questionable. In this paper, we report on the $\ensuremath{\gamma}$-ray spectra from individual neutron resonances from the $^{96}\mathrm{Zr}(n,\ensuremath{\gamma})$ reaction, with an emphasis on the sensitivity of of the $\ensuremath{\gamma}$-ray spectra to different PSF models. The comparison of the measured $\ensuremath{\gamma}$-ray spectra with predicted spectra does not support the addition of a low-energy enhancement of the size reported in many charged-particle reaction measurements, but the sensitivity of the $\ensuremath{\gamma}$-ray spectra to different PSF models is weak.

In this study we used a nonequilibrium simulation method to investigate the temperature dependent divergence of thermal conductivity in a one-dimensional momentum conserving system with an asymmetric double well nearest-neighbor interaction potential. We show that across all temperatures thermal conductivity exhibits power-law divergence with the chain length and the value of the divergence exponent (α) depends on the temperature of the system. At low and high temperatures α reaches close to ∼0.5 and ∼0.33, respectively. Whereas in the intermediate temperature the divergence of thermal conductivity with the chain length saturates with α∼0.07. Subsequent analysis showed that the estimated value of α in the intermediate temperature may not have reached its thermodynamic limit. Further calculations of local α revealed that its approach towards the thermodynamic limit is crucially dependent on the temperature of the system. At low and high temperatures local α reaches its thermodynamic limits in shorter chain lengths. On the contrary, in the case of intermediate temperature its progress towards the asymptotic limit is nonmonotonic.

Brain connectivity and structure-function relationships are analyzed from a physical perspective in place of common graph-theoretic and statistical approaches that overwhelmingly ignore the brain's physical structure and geometry. Field theory is used to define connectivity tensors in terms of bare and dressed propagators, and discretized representations are implemented that respect the physical nature and dimensionality of the quantities involved, retain the correct continuum limit, and enable diagrammatic analysis. Eigenfunction analysis is used to simultaneously characterize and probe patterns of brain connectivity and activity, in place of statistical or phenomenological patterns. Physically based measures that characterize the connectivity are then developed in coordinate and spectral domains; some of which generalize or rectify graph-theoretic measures to implement correct dimensionality and continuum limits, and some replace graph-theoretic quantities. Traditional graph-based measures are shown to be highly prone to artifacts introduced by discretization and threshold, often because essential physical constraints have not been imposed, dimensionality has not been included, and/or distinctions between scalar, vector, and tensor quantities have not been considered. The results can replace them in ways that converge correctly and measure properties of brain structure, rather than of its discretization, and thus potentially enable physical interpretation of the many phenomenological results in the literature. Geometric effects are shown to dominate in determining many brain properties and care must be taken not to interpret geometric differences as differences in intrinsic neural connectivity. The results demonstrate the need to use systematic physical methods to analyze the brain and the potential of such methods to obtain new insights from data, make new predictions for experimental test, and go beyond phenomenological classification to dynamics and mechanisms.

We introduce a simple, exactly solvable strong-randomness renormalization group (RG) model for the many-body localization (MBL) transition in one dimension. Our approach relies on a family of RG flows parametrized by the asymmetry between thermal and localized phases. We identify the physical MBL transition in the limit of maximal asymmetry, reflecting the instability of MBL against rare thermal inclusions. We find a critical point that is localized with power-law distributed thermal inclusions. The typical size of critical inclusions remains finite at the transition, while the average size is logarithmically diverging. We propose a two-parameter scaling theory for the many-body localization transition that falls into the Kosterlitz-Thouless universality class, with the MBL phase corresponding to a stable line of fixed points with multifractal behavior., Comment: Published version

The low-temperature representation for the quark condensate in a weak magnetic field $H$ is known up to two-loop order. Remarkably, at one-loop order, the published series for the quark condensate in the chiral limit and $H \ll T^2$ are inconsistent. Using an alternative representation for the kinematical Bose functions, we derive the series to arbitrary order in $H/T^2$, and also determine which of the published results is correct., Comment: 17 pages, 1 figure

We theoretically investigate the role of the interfacial Rashba spin-orbit coupling in spin pumping based on a nonperturbative calculation. A nonmonotonic behavior is predicted in the Rashba-strength dependence of the Gilbert damping coefficients. We show that the in-plane damping component can exceed the Sharvin limit thanks to the Rashba-field-induced torque. Nevertheless, the pumped spin current remains below the Sharvin limit and satisfies the Onsager reciprocity relations with the spin-current-induced spin-transfer torque.

Macroscopic properties of heterogeneous materials, including thermal and electrical conductivity, elastic moduli, and fluid permeability, depend crucially on their microstructure. Optimal design of such materials with desired properties, as well as characterization of their microstructure, are fundamental problems that have been studied for a long time. Accurate characterization of the microstructure is possible if several $n$-point correlation functions that describe their statistical properties can be computed. While the limits $n=1$, corresponding to phase fractions, and $n=2$, that represents such two-point correlation functions as the radial distribution function, have yielded useful information and insights and have been utilized for reconstruction of models of heterogeneous materials, in many cases higher-order correlation functions are required in order to develop deeper understanding of materials' properties, as well as obtaining accurate estimates for them. We describe an algorithm for computing third-order correlation functions. We test the accuracy of the algorithm for a model of fully penetrable disks, i.e., the so-called cherry-pit model in the limit of the penetrability parameter $\ensuremath{\lambda}=0$, for which an exact expression for the three-point probability function ${S}_{3}({\mathbf{x}}_{1},{\mathbf{x}}_{2},{\mathbf{x}}_{3})$ is known. Excellent agreement between the computed results and the theoretical predictions is demonstrated. We then report on the results of extensive computations for several types of heterogeneous materials and the analysis of their three-point correlation functions. They include the probability and cluster functions ${S}_{3}$ and ${C}_{3}$, as well as the three-point surface and surface-surface-void correlation functions ${F}_{sss}$ and ${F}_{ssv}$, for a variety of two- and three-dimensional disordered materials and media.

It was previously argued that generalized uncertainty principle (GUP) with a positive parameter removes the Chandrasekhar limit. One way to restore the limit is by taking the GUP parameter to be negative. In this work we discuss an alternative method that achieves the same effect: by including a cosmological constant term in the GUP (known as "extended GUP" in the literature). We show that an arbitrarily small but nonzero cosmological constant can restore the Chandrasekhar limit. We also remark that if the extended GUP is correct, then the existence of white dwarfs gives an upper bound for the cosmological constant, which -- while still large compared to observation -- is approximately 86 orders of magnitude smaller than the natural scale., Comment: 7 pages, 5 figures. Improved discussions accepted by PRD

A violation of the Wiedemann-Franz law in a metal can be quantified by comparing the Lorentz ratio, $L=\kappa\rho/T$, where $\kappa$ is the thermal conductivity and $\rho$ is the electrical resistivity, with the universal Sommerfeld constant, $L_0=(\pi^2/3) (k_B/e)^2$. We obtain the Lorentz ratio of a clean compensated metal with intercarrier interaction as the dominant scattering mechanism by solving exactly the system of coupled integral Boltzmann equations. The Lorentz ratio is shown to assume a particular simple form in the forward-scattering limit: $L/L_0=\overline{\Theta^2}/2$, where $\Theta$ is the scattering angle. In this limit, $L/L_0$ can be arbitrarily small. We also show how the same result can be obtained without the benefit of an exact solution. We discuss how a strong downward violation of the Wiedemann-Franz law in a type-II Weyl semimetal WP$_2$ can be explained within our model., Comment: published version, 15 pages, 2 figures

The emergence of quantum statistical mechanics from individual pure states of closed many-body systems is currently under intensive investigations. While most efforts have been put on the impacts of the direct interaction (i.e., the usual mutual interaction) between particles, here we study systematically and analytically the impacts of the exchange interaction, that arises from the particle indistinguishability. We show that this interaction leads an overwhelming number of Fock states to exhibit a structure, that can be resolved only by observables adjusted according to system's dynamical properties and from which thermal distributions emerge. This hidden thermal structure in Fock space is found to be related to the so-called limit shape of random geometric objects in mathematics. The structure enables us to uncover, for both ideal and nonideal Fermi gases, new mechanisms for the emergence of quantum statistical mechanics from individual eigenstates., 6 pages, 3 figures

We analyze amplitude death (AD) in large systems of globally coupled oscillators with randomly distributed time scales. We show that the distribution of characteristic eigenvalues of a large but finite system is well approximated by the continuous and discrete spectra of the system in the thermodynamic limit. The stability analysis from the continuous and discrete spectra of the infinite system provides a fairly accurate prediction for the onset of AD in the large finite system. We prove the argument by examining the stability of AD in a paradigmatic system of coupled Stuart-Landau limit cycles with mismatched time scales. The proposed technique is extended to systems of globally coupled nonlinear oscillators of a general form with time-scale diversity, which is verified in coupled chaotic R\"ossler oscillators. Our study provides analytical insight into the understanding of the emergence of AD in populations of globally coupled dynamical systems.

Using the Gaussian pair fluctuation theory, we investigate quantum fluctuations of a strongly interacting two-dimensional chiral \textit{p}-wave Fermi superfluid at the transition from a Bose-Einstein condensate (BEC) to a topologically non-trivial Bardeen-Cooper-Schrieffer (BCS) superfluid. Near the topological phase transition at zero chemical potential, $\mu=0$, we observe that quantum fluctuations strongly renormalize the zero-temperature equations of state, sound velocity, pair-breaking velocity, and Berezinskii-Kosterlitz-Thouless (BKT) critical temperature of the Fermi superfluid, all of which can be non-analytic functions of the interaction strength. The indication of non-analyticity is particularly evident in the BKT critical temperature, which also exhibits a pronounced peak near the topological phase transition. Across the transition and towards the BEC limit we find that the system quickly becomes a trivial interacting Bose liquid, whose properties are less dependent on the interparticle interaction. The qualitative behavior of composite bosons in the BEC limit remains to be understood., Comment: 13 pages, 8 figures

We investigate sharing of bipartite entanglement in a scenario where half of an entangled pair is possessed and projectively measured by one observer, called Alice, while the other half is subjected to measurements performed sequentially, independently, and unsharply, by multiple observers, called Bobs. We find that there is a limit on the number of observers in this entanglement distribution scenario. In particular, for a two-qubit maximally entangled initial shared state, no more than 12 Bobs can detect entanglement with a single Alice for arbitrary, possibly unequal, sharpness parameters of the measurements by the Bobs. The number of Bobs remains unaltered for a finite range of near-maximal pure initial entanglement, a feature that also occurs in the case of equal sharpness parameters at the Bobs. Furthermore, we show that for nonmaximally entangled shared pure states, the number of Bobs decreases with the amount of initial entanglement, providing a coarse-grained but operational measure of entanglement.

Ultracold atomic gases are an important testing ground for understanding few-body physics. In particular, these systems enable a detailed study of the Efimov effect. We use ultracold $^{39}\mathrm{K}$ to investigate the temperature dependence of an Efimov resonance. The shape and position of the observed resonance are analyzed by employing an empirical fit, and universal finite-temperature zero-range theory. Both procedures suggest that the resonance position shifts towards lower absolute scattering lengths when approaching the zero-temperature limit. We extrapolate this shift to obtain an estimate of the three-body parameter at zero temperature. A surprising finding of our study is that the resonance becomes less prominent at lower temperatures, which currently lacks a theoretical description and implies physical effects beyond available models. Finally, we present measurements performed near the Feshbach resonance center and discuss the prospects for observing the second Efimov resonance in $^{39}\mathrm{K}$.

We analyze the passage to a continuum limit of the mode spectrum of primordial perturbations around flat cosmological spacetimes in Quantum Cosmology, showing that this limit can be reached even if one starts by considering a finite fiducial cell as spatial slice. Whereas the resulting system can be described in an invariant way under changes of the fiducial volume using appropriate variables, both for the background cosmology and the perturbations, obtaining in this way a discrete mode spectrum owing to the compactness of the fiducial cell, we show that the desired continuum limit for the perturbations can still be established by means of scaling transformations of the physical volume when this volume grows unboundedly. These transformations lead to a model with a continuum of modes and independent of any scale of reference for the physical volume. For the sake of comparison, we also consider an alternative road to the continuum in Fourier space that has been employed in geometrodynamics and is based on the use of scaling transformations of the fiducial volume, together with variables that are independent of them., Comment: 12 pages

Background: Observation of lepton number violation via detection of neutrinoless double $\ensuremath{\beta}$ decay requires that the neutrino be a Majorana particle. If the neutrino is a Dirac particle, a potential lepton-number violating process is neutrinoless quadruple $\ensuremath{\beta}$ decay. Only a few nuclei can undergo neutrinoless quadruple $\ensuremath{\beta}$ decay; one of these nuclei is $^{150}\mathrm{Nd}$.Purpose: This study yields the first half-life limit of the neutrinoless quadruple $\ensuremath{\beta}$ decay to the excited ${0}_{1}^{+}$ state of $^{150}\mathrm{Gd}$.Methods: We searched for neutrinoless quadruple $\ensuremath{\beta}$ decay events to excited final states of $^{150}\mathrm{Gd}$ by detecting the deexcitation $\ensuremath{\gamma}$ rays of the daughter nucleus in coincidence. These $\ensuremath{\gamma}$ rays have energies of 569.031 and 638.050 keV, and are emitted in coincidence through a ${0}_{1}^{+}\ensuremath{\rightarrow}{2}_{1}^{+}\ensuremath{\rightarrow}{0}_{gs}^{+}$ transition.Results: The enriched ${\mathrm{Nd}}_{2}{\mathrm{O}}_{3}$ sample consisted of $40.33\ifmmode\pm\else\textpm\fi{}0.02$ g $^{150}\mathrm{Nd}$ and was observed for 642.8 days at the Kimballton Underground Research Facility. A half-life limit for the decay to the ${0}_{1}^{+}$ state of $^{150}\mathrm{Gd}$ was found to be ${T}_{1/2}g1.76\ifmmode\times\else\texttimes\fi{}{10}^{20}$ years (90% CL).Conclusions: We report the first search for this decay to excited final states. Though the predicted half-life of this decay is many orders of magnitudes larger, constraining this value experimentally is vital to check for potential enhancements to the decay rate.

In this paper we present an efficient method for constraining both thermal and non-thermal Dark Matter (DM) scenarios with the Lyman-$\alpha$ forest, based on a simple and flexible parametrisation capable to reproduce the small scale clustering signal of a large set of non-cold DM (nCDM) models. We extract new limits on the fundamental DM properties, through an extensive analysis of the high resolution, high redshift data obtained by the MIKE/HIRES spectrographs. By using a large suite of hydrodynamical simulations, we determine constraints on both astrophysical, cosmological, and nCDM parameters by performing a full Monte Carlo Markov Chain (MCMC) analysis. We obtain a marginalised upper limit on the largest possible scale at which a power suppression induced by nearly any nCDM scenario can occur, i.e. $\alpha, Comment: 17 pages, 9 figures, 3 tables. Accepted by PRD

We study the current of Bose particles between two reservoirs connected by a one-dimensional channel. We analyze the problem from first principles by considering a microscopic model of conductivity in the noninteracting limit. Equations for the transient and the stationary current are derived analytically. The asymptotic current has a form similar to the Landauer-B\"uttiker equation for electronic current in mesoscopic devices.

We explore possible non-Gaussian features of primordial gravitational waves by constructing model-independent templates for nonlinearity parameters of tensor bispectrum. Our analysis is based on Effective Field Theory of inflation that relies on no particular model as such and thus the results are quite generic. The analysis further reveals that chances of detecting squeezed limit tensor bispectrum are fairly higher than equilateral limit. We also discuss prospects of detectability in upcoming CMB missions., 5 pages, 2 figures. To appear in Phys.Rev.D

We analyze a family of two-dimensional BCS Hamiltonians with general l-wave pairing interactions, classifying the models in this family that are Bethe-ansatz solvable in the finite-size regime. We show that these solutions are characterized by nontrivial winding numbers, associated with topological phases, in some part of the corresponding phase diagrams. By means of a comparative study, we demonstrate benefits and limitations of the mean-field approximation, which is the standard approach in the limit of a large number of particles. The mean-field analysis also allows to extend part of the results beyond integrability, clarifying the peculiarities associable with the integrability itself.

We present a functional renormalization-group approach to interacting topological Green's function invariants with a focus on the nature of transitions. The method is applied to chiral symmetric fermion chains in the Mott limit that can be driven into a Haldane phase. We explicitly show that the transition to this phase is accompanied by a zero of the fermion Green's function. Our results for the phase boundary are quantitatively benchmarked against density matrix renormalization-group data.

We investigate by numerical simulation and finite-size analysis the impact of long-range shortcuts on a spatially embedded transportation network. Our networks are built from two-dimensional ($d=2$) square lattices to be improved by the addition of long-range shortcuts added with probability $P(r_{ij})\sim r_{ij}^{-\alpha}$ [J. M. Kleinberg, Nature 406, 845 (2000)]. Considering those improved networks, we performed numerical simulation of multiple discrete package navigation and found a limit for the amount of packages flowing through the network. Such limit is characterized by a critical probability of creating packages $p_{c}$, where above this value a transition to a congested state occurs. Moreover, $p_{c}$ is found to follow a power-law, $p_{c}\sim L^{-\gamma}$, where $L$ is the network size. Our results indicate the presence of an optimal value of $\alpha_{\rm min}\approx1.7$, where the parameter $\gamma$ reaches its minimum value and the networks are more resilient to congestion for larger system sizes., Comment: 7 pages, 5 figures

ZrSiS is one of the strong candidates for realistic nodal-line semimetal. We theoretically investigate the dynamical conductivity in ZrSiS by using a multi-orbital theoretical model based on the first-principles band calculation. We find that the dynamical conductivity in the clean limit is actually not frequency independent unlike the ideal Dirac model, while nearly flat dependence is achieved by introducing the energy broadening possibly induced by the disorder. The results can be applied to other compounds with the similar crystal structure, such as ZrSiSe, ZrSiTe, and HfSiS., Comment: 6 pages, 7 figures

We study the field theory for the SU($N_c$) symmetric antiferromagnetic quantum critical metal with a one-dimensional Fermi surface embedded in general space dimensions between two and three. The asymptotically exact solution valid in this dimensional range provides an interpolation between the perturbative solution obtained from the $\epsilon$-expansion near three dimensions and the nonperturbative solution in two dimensions. We show that critical exponents are smooth functions of the space dimension. However, physical observables exhibit subtle crossovers that make it hard to access subleading scaling behaviors in two dimensions from the low-energy solution obtained above two dimensions. These crossovers give rise to noncommutativities, where the low-energy limit does not commute with the limits in which the physical dimensions are approached., Comment: 34 pages: 12 pages for the main text, the remaining are supplementary materials. 25 figures and 2 tables. v2: minor revision and references updated. To appear in PRB