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We present an approach to spin dynamics by extending the optical Bloch equations for the driven two-level system to derive microscopic expressions for the transverse and longitudinal spin relaxation times. This is done for the 6-level…

Other Condensed Matter · Physics 2009-11-10 C. Lechner , U. Roessler

We extend a microscopic theory of polarization and magnetization to include the spin degree of freedom of the electrons, introducing a general spin orbit coupling and Zeeman interaction term in the Hamiltonian. At finite frequencies and…

Mesoscale and Nanoscale Physics · Physics 2023-07-11 Alistair H. Duff , J. E. Sipe

We study the ground-state entanglement of one-dimensional harmonic chains that are coupled to each other by a collective interaction as realized e.g. in an anisotropic ion crystal. Due to the collective type of coupling, where each chain…

Quantum Physics · Physics 2013-05-29 R. G. Unanyan , M. Fleischhauer , D. Bruss

By going beyond Hubbard Hamiltonian we reflected correlation effects accurately in the wavefunctions of H2. Using ab initio e-e interaction parameters resulted maximally entangled ground and third excited states. We assigned this maximally…

Quantum Physics · Physics 2010-07-20 M. Babamoradi , M. Heidari Saani , M. A. Vesaghi

We discuss orbital entanglement in mesoscopic conductors, focusing on the effect of dephasing. The entanglement is detected via violation of a Bell Inequality formulated in terms of zero-frequency current correlations. Following closely the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 P. Samuelsson , E. Sukhorukov , M. Buttiker

The exchange interaction among electrons is one of the most fundamental quantum mechanical interactions in nature and underlies any magnetic phenomena from ferromagnetic ordering to magnetic storage. The current technology is built upon a…

Materials Science · Physics 2015-05-20 G. P. Zhang , M. S. Si , Y. H. Bai , Thomas F. George

We theoretically study the entanglement between two arbitrary spins in a magnetic material, where magnons naturally form a general squeezed coherent state, in the presence of an applied magnetic field and axial anisotropies. Employing…

Mesoscale and Nanoscale Physics · Physics 2020-01-22 Ji Zou , Se Kwon Kim , Yaroslav Tserkovnyak

Entanglement of spins is analyzed for two electrons extracted from a mixed many electron state by projecting onto the two-electron subspace. The concurrence formulae are expressed in a compact form for states with a well defined square of…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 A. Ramsak , J. Mravlje , T. Rejec , A. Lautar

Nonlinear charge transport in strongly coupled semiconductor superlattices is described by Wigner-Poisson kinetic equations involving one or two minibands. Electron-electron collisions are treated within the Hartree approximation whereas…

Mesoscale and Nanoscale Physics · Physics 2008-11-16 L. L. Bonilla , L. Barletti , M. Alvaro

We discuss the estimation of the distance of a given mixed many-body quantum state to the set of fully separable states, applied to the concrete scenario of collective spin states. Concretely, we discuss lower bounds to distances from the…

Quantum Physics · Physics 2026-04-22 Julia Mathé , Ayaka Usui , Otfried Gühne , Giuseppe Vitagliano

We extend the criteria for $k$-particle entanglement from the spin squeezing parameter presented in [A.S. S{\o}rensen and K. M{\o}lmer, Phys. Rev. Lett. {\bf 86}, 4431 (2001)] to systems with a fluctating number of particles. We also…

Quantum Physics · Physics 2012-09-17 Philipp Hyllus , Luca Pezze , Augusto Smerzi , Geza Toth

We investigate a possibility of pair electron-electron e-e collisions in a ballistic wire with spin-orbit coupling and only one populated mode. Unlike in a spin-degenerate system, a combination of spin-splitting in momentum space with a…

Mesoscale and Nanoscale Physics · Physics 2018-09-12 V. S. Khrapai , K. E. Nagaev

The minimum requirements for entanglement detection are discussed for a spin chain in which the spins cannot be individually accessed. The methods presented detect entangled states close to a cluster state and a many-body singlet state, and…

Quantum Physics · Physics 2007-05-23 Geza Toth

Entanglement can be generated by two electrons in a spin-zero state on a semiconducting single-walled carbon nanotube. The two electrons, one weakly bound in a shallow well in the conduction band, and the other injected into the conduction…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 D. Gunlycke , J. H. Jefferson , T. Rejec , A. Ramsak , D. G. Pettifor , G. A. D. Briggs

Shuttling of electrons in single-molecule transistors with magnetic leads in the presence of an external magnetic field is considered theoretically. For a current of partially spin-polarized electrons a shuttle instability is predicted to…

Mesoscale and Nanoscale Physics · Physics 2015-07-22 O. A. Ilinskaya , S. I. Kulinich , I. V. Krive , R. I. Shekhter , Y. W. Park , M. Jonson

We derive a lower limit to the amount of absorptive loss present in passive linear optical devices such as a beam splitter. We choose a particularly simple beam splitter geometry, a single planar slab surrounded by vacuum, which already…

Quantum Physics · Physics 2009-11-11 Stefan Scheel

We investigate relaxation and dephasing of an electron spin confined in a semiconductor quantum dot and subject to spin-orbit coupling. Even in vanishing magnetic field, B = 0, slow noise coupling to the electron's orbital degree of freedom…

Mesoscale and Nanoscale Physics · Physics 2007-12-03 Pablo San-Jose , Gerd Schön , Alexander Shnirman , Gergely Zarand

Studying the physics of quantum correlations has gained new interest after it has become possible to measure entanglement entropies of few body systems in experiments with ultracold atomic gases. Apart from investigating trapped atom…

Quantum Physics · Physics 2020-09-22 Arkadiusz Kuroś , Anna Okopińska

We study the spin-dependent conductance of ballistic mesoscopic ring systems in the presence of an inhomogeneous magnetic field. We show that, for the setup proposed, even a small Zeeman splitting can lead to a considerable spin…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Markus Popp , Diego Frustaglia , Klaus Richter

We show how entanglement may be quantified in spin and cold atom many-body systems using standard experimental techniques only. The scheme requires no assumptions on the state in the laboratory and a lower bound to the entanglement can be…

Quantum Physics · Physics 2013-05-29 M. Cramer , M. B. Plenio , H. Wunderlich