Physics of Particles and Nuclei最新文献

A formulation of quantum mechanics based on replacing the general unitary group by finite groups is considered. To solve problems arising in the context of this formulation, we use computer algebra and computational group theory methods.

Search for reactions with nucleon charge exchange in the fragmentation of carbon nuclei with the energy of 300 MeV/nucleon on a thin beryllium target is performed on the FRAGM fragment separator of the TWAC accelerator complex. The experimental setup arranged at the angle of 3.5° with respect to the incident beam has a high momentum resolution. Differential cross sections for yields of ¹¹Be, ¹²B, and ¹²Be nuclei are measured as a function of the momentum of these nuclei. The experimental data are compared with theoretical predictions of various nucleus–nucleus interaction models and other experimental results. Nucleon charge-exchange processes in this energy range are measured for the first time. New data are obtained for verification of theoretical models of nucleus–nucleus interactions.

This article presents a technology being developed for the design of an intelligent robust control system based on quantum and soft computing. The corresponding software tools and stages of creating an embedded control system are presented. In particular, the application of soft computing, fuzzy logic, fuzzy neural networks, and evolutionary and quantum computing using quantum-inspired algorithms implemented on classical processors is considered. As an illustrative example, the problem of controlling refrigerant pressure during testing of superconducting magnets is addressed. The results of applying a coordination control system with an integrated quantum controller are presented.

The issue of the dichotomy between the elementary and composite nature of a finite-dimensional quantum system is discussed within the framework of the generalized Stratonovich–Weyl formulation of quantum mechanics. Performing numerical studies, we demonstrate how information on the possibility of realizing a virtual 2-level subsystem is encoded in the properties of the Wigner function of a total 4-level system.

We consider an (n)-qubit quantum system with a Hamiltonian, defined by an expansion in the Pauli basis, and propose a new algorithm for classical computing the exponential of the Hamiltonian. The algorithm is based on the representation of the exponential by the Dunford–Cauchy integral, followed by an efficient computation of the resolvent, and is suitable for Hamiltonians that are sparse in the Pauli basis. The practical efficiency of the algorithm is demonstrated by two illustrative examples.

The model of multi-level open quantum system interacting with a non-vacuum reservoir in the rotating wave approximation is considered. We provide an exact integral representation for the reduced density matrix of the system. For identical uncorrelated reservoirs in diagonal states we have obtained the first perturbative correction for such dynamics in the Bogolubov–van Hove limit. We have shown that after initial state renormalization it can be completely described in terms of finite-dimensional semigroup. The method we provide can also be applied to the further orders of perturbation theory with Bogolubov–van Hove scaling.

In this paper, we consider the problem of searching for an element in a dictionary. Various approaches to solving this problem have been proposed in recent decades: classical and quantum algorithms. We present two algorithms: a hybrid classical-quantum algorithm [1], that implements Grover’s search, and a “pure” quantum algorithm based on the quantum fingerprinting technique. Both algorithms work (a) with a high probability of obtaining the correct result and (b) with a quadratic query acceleration compared to the classical one. Our algorithms are much more memory efficient in terms of the number of qubits used compared to previously known quantum algorithms.

A measure of entanglement production by quantum operations is suggested. This measure is general, being valid for operations over pure states as well as over mixed states, for equilibrium as well as for nonequilibrium processes. The measure of entanglement production satisfies all properties typical of such a characteristic. Systems of arbitrary nature can be treated, described by field operators, spin operators, or any other operators, which is realized by defining generalized correlation matrices. Particular cases of entanglement production are considered.

In this universe, the matter-antimatter asymmetry is one of the major mysteries. This baryonic asymmetry can not be fully described within the current frame of standard model rather than we need to go beyond standard model of physics (BSM) but the main problem of BSM is that it is restricted by many complicated boundaries. In search of BSM, we need to prove CPT violation in nature, though CP violation has been observed already but this violation anticipated by the standard model is very small to describe the magnitude of baryonic asymmetry and search for T-violation is still ongoing. Neutron Optics Parity and Time Reversal Experiment (NOPTREX) is one such experiment that is working on the larger search for proof of time reversal violation(TRV). This experiment specifically seeks to investigate time-reversal violation in neutron interactions with heavy nuclei under specific conditions of narrow neutron-nuclear resonances, particularly focusing on orbital angular momentum L = 1. The investigation involves examining potential phase shifts in the transmitted neutron wave function, specifically looking at a term represented by (S = {{sigma }_{n}}({{k}_{n}} times I)), where ({{sigma }_{n}}) denotes the neutron spin, ({{k}_{n}}) signifies the neutron momentum, and I represents the nucleus spin.This paper delves into the historical evolution of research on Time Reversal Violation (TRV), offering insights into the core concept of time reversal symmetry and its significance in modern physics. This review work will provide an overview of the NOPTREX experiment’s setup, findings, and its exploration of TRV in neutral meson decays under conditions devoid of magnetic fields, meticulously examining the outcomes and past, present and future of the NOPTREX experiment.