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We investigate quantum entanglement in two-spin-1/2 NMR systems at thermal equilibrium under external magnetic fields. We derive closed-form analytical expressions for the entanglement of the system and show how the entanglement depends on…

Quantum Physics · Physics 2025-12-02 Fatemeh Khashami , Stefan Glöggler

In this work we analyze the nonequilibrium transport through a quantum impurity (quantum dot or molecule) attached to ferromagnetic leads by using a hybrid numerical renormalization group-time-dependent density matrix renormalization group…

Mesoscale and Nanoscale Physics · Physics 2022-10-05 Anand Manaparambil , Andeas Weichselbaum , Jan von Delft , Ireneusz Weymann , .

We recently derived a spin-mapping approach for treating the nonadiabatic dynamics of a two-level system in a classical environment [J. Chem. Phys. 151, 044119 (2019)] based on the well-known quantum equivalence between a two-level system…

Chemical Physics · Physics 2020-03-03 Johan E. Runeson , Jeremy O. Richardson

A quantum dot coupled to ferromagnetically polarized one-dimensional leads is studied numerically using the density matrix renormalization group method. Several real space properties and the local density of states at the dot are computed.…

Strongly Correlated Electrons · Physics 2007-05-23 C. J. Gazza , M. E. Torio , J. A. Riera

We consider an atomic quantum dot confined between two weakly-coupled Bose-Einstein condensates, where the dot serves as an additional tunneling channel. It is shown that the thus-embedded atomic quantum dot is a pseudospin subject to an…

Other Condensed Matter · Physics 2007-05-23 Ingrid Bausmerth , Uwe R. Fischer , Anna Posazhennikova

Using one-dimensional spin-orbital model as a typical example of quantum spin systems with richer symmetries, we study the effect of an isolated impurity on its low energy dynamics in the gapless phase through bosonization and…

Strongly Correlated Electrons · Physics 2009-10-31 Yu-Wen Lee , Yu-Li Lee

We theoretically investigate the dynamical nuclear spin polarization in a quantum point contact (QPC) at finite magnetic field. We find that when the QPC is tuned to be spin selective, at the conductance of e^2/h, a finite bias induces a…

Mesoscale and Nanoscale Physics · Physics 2018-03-20 Peter Stano , Tomosuke Aono , Minoru Kawamura

Semiconductor quantum dots (QDs) offer a platform to explore the physics of quantum electronics including spins. Electron spins in QDs are considered good candidates for quantum bits in quantum information processing, and spin control and…

Spin-boson models are simple examples of quantum dissipative systems, but also serve as effective models in quantum magnetism and exhibit nontrivial criticality. Recently, they have been established as a platform to study the nontrivial…

Strongly Correlated Electrons · Physics 2026-01-06 Manuel Weber

We demonstrate how robust entanglement of quantum dot molecular system in a voltage controlled junction can be generated. To improve the quantum information characteristics of this system, we propose an applicable protocol which contains…

Quantum Physics · Physics 2019-06-13 Elaheh Afsaneh , Malek Bagheri Harouni

We apply the non-perturbative renormalization group method to a class of out-of-equilibrium phase transitions (usually called ``parity conserving'' or, more properly, ``generalized voter'' class) which is out of the reach of perturbative…

Statistical Mechanics · Physics 2007-05-23 L. Canet , H. Chaté , B. Delamotte , I. Dornic , M. A. Muñoz

We study quantum dynamical properties of a spin-1 atomic Bose-Einstein condensate in a double-well potential. Adopting a mean field theory and single spatial mode approximation, we characterize our model system as two coupled spins. For…

Quantum Physics · Physics 2009-11-11 Ö. E. Müstecaplıoğlu , M. Zhang , L. You

Magnetic properties of two and three-dimensional clusters of quantum dots are studied with exact diagonalization of a generalized Hubbard model. We study the weak coupling limit, where the electrons interact only within a quantum dot and…

Strongly Correlated Electrons · Physics 2009-11-13 J. -P. Nikkarila , M. Koskinen , M. Manninen

In the Abelian-Higgs model, or Ginzburg-Landau model of superconductivity, the existence of an infrared stable charged fixed point ensures that there is a parameter range where the superconducting phase transition is second order, as…

High Energy Physics - Theory · Physics 2019-07-22 Aron J. Beekman , Gergely Fejős

Nonlinear transport through a quantum dot is studied in the limit of weak and strong intra-dot Coulomb interaction. For the latter regime the nonequilibrium self-consistent mean field equations for energies and spectral weights of…

Strongly Correlated Electrons · Physics 2007-05-23 I. Sandalov , R. G. Nazmitdinov

We study quantum gravity in more than four dimensions with renormalisation group methods. We find a non-trivial ultraviolet fixed point in the Einstein-Hilbert action. The fixed point connects with the perturbative infrared domain through…

High Energy Physics - Theory · Physics 2008-11-26 Peter Fischer , Daniel F. Litim

We investigate a spin-full double quantum dot (DQD) coupled to the leads in a pseudospin valve configuration. The interplay of interaction and interference produces in the stability diagram a rich variety of resonances, modulated by the…

Mesoscale and Nanoscale Physics · Physics 2021-05-26 Christoph Rohrmeier , Andrea Donarini

Non-equilibrium spin transport through an interacting quantum dot is analyzed. The coherent spin oscillations in the dot provide a generating source for spin current. In the interacting regime, the Kondo effect is influenced in a…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Ping Zhang , Qi-Kun Xue , X. C. Xie

The inclusion of charging and spin-exchange interactions within the Universal Hamiltonian description of quantum dots is challenging as it leads to a non-Abelian action. Here we present an {\it exact} analytical solution of the probem, in…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 I. S. Burmistrov , Yuval Gefen , M. N. Kiselev

Inhomogeneities and junctions in wires are natural sources of scattering, and hence resistance. A conducting fixed point usually requires an adiabatically smooth system. One notable exception is "healing", which has been predicted in…

Strongly Correlated Electrons · Physics 2014-01-28 N. Sedlmayr , D. Morath , J. Sirker , S. Eggert , I. Affleck