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The transfer of quantum information between many-qubit states is a subject of fundamental importance in quantum science and technology. We consider entanglement swapping in critical quantum spin chains, where the entanglement between the…

Quantum Physics · Physics 2025-04-28 Masahiro Hoshino , Masaki Oshikawa , Yuto Ashida

The present paper is a short review of different path integral representations of the partition function of quantum spin systems. To begin with, I consider coherent states for SU(2) algebra. Different parameterizations of the coherent…

Strongly Correlated Electrons · Physics 2012-11-20 Naoum Karchev

A general formula is obtained for Yukawa couplings in compactification on \LGO{s} and corresponding \CY\ spaces. Up to the kinetic term normalizations, this equates the classical Koszul ring structure with the \LGO\ chiral ring structure…

High Energy Physics - Theory · Physics 2010-11-01 P. Berglund , T. Hübsch

We present a detailed discussion of entanglement entropy in (1+1)-dimensional Warped Conformal Field Theories (WCFTs). We implement the Rindler method to evaluate entanglement and Renyi entropies for a single interval and along the way we…

High Energy Physics - Theory · Physics 2017-01-19 Alejandra Castro , Diego M. Hofman , Nabil Iqbal

We address the problem of measuring the relative angle between two "quantum axes" made out of N1 and N2 spins. Closed forms of our fidelity-like figure of merit are obtained for an arbitrary number of parallel spins. The asymptotic regimes…

Quantum Physics · Physics 2009-11-11 E. Bagan , S. Iblisdir , R. Munoz-Tapia

In this paper, we introduce a deterministic approach of quantum mechanics for particles with spin 1 2 moving in one dimension. We present a Lagrangian of a spinning particle ($s ={1 \over 2} $), and deduce the expression of the conjugate…

Quantum Physics · Physics 2007-05-23 T. Djama

We examine several well known quantum spin models and categorize behavior of pairwise entanglement at quantum phase transitions. A unified picture on the connection between the entanglement and quantum phase transition is given.

Quantum Physics · Physics 2009-11-11 Shi-Jian Gu , Guang-Shan Tian , Hai-Qing Lin

Entanglement in quantum XY spin chains of arbitrary length is investigated via a recently-developed global measure suitable for generic quantum many-body systems. The entanglement surface is determined over the phase diagram, and found to…

A scheme for generating an entangled state in a two spin-1/2 system by means of a spin-dependent potential scattering of another qubit is presented and analyzed in three dimensions. The entanglement is evaluated in terms of the concurrence…

Quantum Physics · Physics 2010-04-07 Yuichiro Hida , Hiromichi Nakazato , Kazuya Yuasa , Yasser Omar

The spin-isospin response of stable and exotic nuclei is investigated in the framework of the proton-neutron relativistic quasiparticle time-blocking approximation (pn-RQTBA). Based on the Covariant Density Functional Theory, this method…

Nuclear Theory · Physics 2017-07-25 Caroline Robin , Elena Litvinova

We summarize recent developments at the interface of quantum gravity and quantum information, and discuss applications to the quantum geometry of space in loop quantum gravity. In particular, we describe the notions of link entanglement,…

General Relativity and Quantum Cosmology · Physics 2023-08-23 Eugenio Bianchi , Etera R. Livine

Recent work has argued that the concepts of entanglement and nonlocality must be taken seriously even in systems consisting of only a single particle. These treatments, however, are nonrelativistic and, if single particle entanglement is…

Quantum Physics · Physics 2015-05-13 Jacob Dunningham , Vlatko Vedral

We introduce the concept of directional coupling, i.e., the selective transfer of a state between adjacent quantum wires, in the context of quantum computing and short-distance communication. Our analysis rests upon a mathematical analogy…

Quantum Physics · Physics 2008-12-09 Georgios M. Nikolopoulos

Spin-orbital entanglement in the ground state of a one-dimensional SU(2)$\otimes$SU(2) spin-orbital model is analyzed using exact diagonalization of finite chains. For $S=1/2$ spins and $T=1/2$ pseudospins one finds that the quantum…

Strongly Correlated Electrons · Physics 2007-06-19 Andrzej M. Oles , Peter Horsch , Giniyat Khaliullin

In this report, we examine the relaxation phenomena of a spin qubit coupled to a spin chain with a $1/r^2$ interaction.

Mesoscale and Nanoscale Physics · Physics 2008-04-18 Toshifumi Itakura

We investigate entanglement of spin pairs in alternating open spin chains in the equilibrium state in an external magnetic field. We calculate the reduced density matrix of spin pairs and estimate the concurrence with Wootter's criteria.…

Quantum Physics · Physics 2009-11-13 S. I. Doronin , E. B. Fel'dman , A. N. Pyrkov

We consider pure quantum states of $N\gg 1$ spins or qubits and study the average entanglement that can be \emph{localized} between two separated spins by performing local measurements on the other individual spins. We show that all…

Quantum Physics · Physics 2007-05-23 F. Verstraete , M. Popp , J. I. Cirac

The gravitational couplings of intrinsic spin are briefly reviewed. A consequence of the Dirac equation in the exterior gravitational field of a rotating mass is considered in detail, namely, the difference in the energy of a spin-1/2…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Bahram Mashhoon

We describe some field theoretic methods for studying quantum spin systems in one dimension. These include the nonlinear sigma-model approach which is particularly useful for large values of the spin, the idea of Luttinger liquids and…

Strongly Correlated Electrons · Physics 2007-05-23 Diptiman Sen

The hypothesis of coupling between spin and rotation introduced long ago by Mashhoon is examined in the context of "1+3" and "3+1" space-time splitting techniques, either in special or in general relativity. Its content is discussed in…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Donato Bini , Luca Lusanna