Modern Physics Letters A

The hypothetical nonlocal box (NLB) proposed by Popescu and Rohrlich allows two spatially separated parties, Alice and Bob, to exhibit stronger than quantum correlations. If the generated correlations are weak, they can sometimes be distilled into a stronger correlation by repeated applications of the NLB. Motivated by the limited distillability of NLBs, we initiate here a study of the distillation of correlations for nonlocal boxes that output quantum states rather than classical bits (qNLBs). We propose a new protocol for distillation and show that it asymptotically distills a class of correlated quantum nonlocal boxes to the value , whereas in contrast, the optimal non-adaptive parity protocol for classical nonlocal boxes asymptotically distills only to the value 3.0. We show that our protocol is an optimal non-adaptive protocol for 1, 2 and 3 qNLB copies by constructing a matching dual solution for the associated primal semidefinite program (SDP). We conclude that qNLBs are a stronger resource for nonlocality than NLBs. The main premise that develops from this conclusion is that the NLB model is not the strongest resource to investigate the fundamental principles that limit quantum nonlocality. As such, our work provides strong motivation to reconsider the status quo of the principles that are known to limit nonlocal correlations under the framework of qNLBs rather than NLBs.

This paper is devoted to locate the position of critical end point (CEP) and study its properties. The CEP for different current quark masses are located. It is found that as the current quark mass tends to zero, the position of the CEP tends to the tricrtical point (TCP), while the height of the chiral susceptibility tends to infinity faster and faster, which indicates that the transition from CEP to TCP is continuous. This continuity causes the so-called hidden TCP effect.

Mixing of fermion and antifermion states occurs in gravitational interactions, leading to non-conservation of fermion number above temperatures determined by the particle masses. We study the evolution of a -system and calculate the cross-sections for the reactions . Their values are identical in both directions. However, if changes quickly into a lighter antiparticle, then the reaction symmetry is broken, resulting in an increased production of matter over antimatter.

This paper is devoted to check the validity of laws of thermodynamics for Kaluza–Klein universe in the state of thermal equilibrium, composed of dark matter and dark energy. The generalized holographic dark energy and generalized Ricci dark energy models are considered here. It is proved that the first and generalized second law of thermodynamics are valid on the apparent horizon for both of these models. Further, we take a horizon of radius L with modified holographic or Ricci dark energy. We conclude that these models do not obey the first and generalized second law of thermodynamics on the horizon of fixed radius L for a specific range of model parameters.

By choosing a fluid source in f(R) gravity, defined by f(R) = R-12aξ ln|R|, where a (Rindler acceleration) and ξ are both constants, the field equations correctly yield the Rindler acceleration term in the metric. We identify domains in which the weak energy conditions (WEC) and the strong energy conditions (SEC) are satisfied.

In this paper, we investigate the representation of the Wigner algebra by using the q-calculus like approach. For this algebra, the coherent state is constructed and the uncertainty relation for the ground state is discussed. Following Wigner's approach, the Wigner deformation of the fermion algebra is obtained and its Fock space is shown to have finite dimension.

The importance of measuring Q-values in rapid proton capture process has been investigated. The microscopic optical model, derived using a nucleon–nucleon interaction and densities from relativistic mean field (RMF) calculations, has been utilized to calculate the reaction rates. It has been observed that the Q-values involved in the reactions at waiting points at A = 60 and 64 are very important in determining the final abundance of the process. Some other Q-values also play a crucial role in the final abundance of nuclei near the end point of the process.