Arxiv Selection Oct 2020

Oct 1- Oct 7 Bhaskar Mukherjee, Oct 8- Oct 14 Zehan Li, Oct 15- Oct 21 Haiping Hu, Oct 22- Oct 28 Sayan Choudhury

Oct 14

arXiv:2010.06560 [pdf, other]

Double-peak specific heat anomaly and correlations in the Bose-Hubbard model

Eduardo O. Rizzatti, Marco Aurélio A. Barbosa, Marcia C. Barbosa

Subjects: Quantum Gases (cond-mat.quant-gas)

Considering the thermodynamics of bosons in a lattice described by the Bose-Hubbard Hamiltonian, we report the occurrence of anomalous double peaks in their specific heat dependence on tempera- ture. This feature, usually associated with a high geometrical frustration, can also be a consequence of a purely energetic competition. By employing self-energy functional calculations combined with finite-temperature perturbation theory, we propose a mechanism based on ground-state degeneracies expressed as residual entropies. A general decomposition of the specific heat regarding all possible transitions between the system’s eingenvalues provides an insight into the nature of each maximum. Furthermore, we address how the model parameters modify the structure of these peaks based on its spectral properties and atom-atom correlation function.

Oct 11

arXiv:2010.05159 [pdf, ps, other] gr-qc hep-th quant-ph

Entanglement and decoherence of massive particles due to gravity

Authors: Daisuke Miki, Akira Matsumura, Kazuhiro Yamamoto

Abstract: We analyze the dynamics of gravity-induced entanglement for N massive particles. Considering a linear configuration of these particles, we investigate the entanglement between a specific pair of particles under the influence of the gravitational interaction between the massive particles. As the particle number increases, the specific particle pair decoheres more easily due to the gravitational int… ▽ More Submitted 15 October, 2020; v1 submitted 11 October, 2020; originally announced October 2020. Comments: 20 pages, 5 figures

Oct 09

arXiv:2010.04443 [pdf, other] quant-ph cond-mat.mes-hall cond-mat.stat-mech

Ring-Frustrated Non-Hermitian XY Model

Authors: Shihao Bi, Yan He, Peng Li

Abstract: We study a non-Hermitian version of XY closed chain with odd number of lattice sites. We consider both anti-ferromagnetic coupling and also a symmetric non-collinear spin coupling. It is found that the energy spectrum is real in certain region of the parameter space. In contrast to previous non-Hermitian models, the ground state is a state with one mode occupied inside this real energy spectrum re… ▽ More Submitted 9 October, 2020; originally announced October 2020. Comments: 5 pages, 5 figures

Oct 08

arXiv:2010.03841 [pdf, ps, other] quant-ph

Efficient unstructured search implementation on current ion-trap quantum processors

Authors: Vladyslav Hlembotskyi, Rafał Burczyński, Witold Jarnicki, Adam Szady, Jan Tułowiecki

Abstract: So far, only the results on 3 qubit spaces (both on superconducting and ion-trap realisations of quantum processors) have beaten the classical unstructured search in the expected number of oracle calls using optimal protocols in both settings. We present experimental results on running unstructured search in spaces defined by 4, 5 and 6 qubits on ion-trapped quantum processor. Our best circuits ob… ▽ More Submitted 8 October, 2020; originally announced October 2020. Comments: 10 pages, 14 figures Report number: 20-10-H