Open Ising Model Perturbed by Classical Colored Noises

The Perturbed Ferromagnetic Chain: A Tuneable Test of Quantum Hardness in the Transverse-Field Ising Model

Quantum annealing in the transverse-field Ising model (TFIM) with open-system dynamics is known to use thermally-assisted tunneling to drive computation. However, it is still subject to debate whether quantum systems in the presence of decoherence are more useful than those using classical dynamics to drive computation. We contribute to this debate by introducing the perturbed ferromagnetic chain (PFC), a chain of frustrated sub-systems where the degree of frustration scales inversely with the perturbation introduced by a tunable parameter. This gives us an easily embeddable gadget whereby pro…

A strong-weak coupling duality between two perturbed quantum many-body systems: CSS codes and Ising-like systems

Graphs and recently hypergraphs have been known as an important tool for considering different properties of quantum many-body systems. In this paper, we study a mapping between an important class of quantum systems namely quantum Calderbank-Shor-Steane (CSS) codes and Ising-like systems by using hypergraphs. We show that the Hamiltonian corresponding to a CSS code on a hypergraph $H$ which is perturbed by a uniform magnetic field is mapped to Hamiltonian of a Ising-like system on dual hypergraph $\tilde{H}$ in a transverse field. Interestingly, we show that a strong regime of couplings in one…

弱扰动Ising模型中的完全宏观热化与薛定谔猫态的形成——Roos-Sugimoto-Teufel-Tumulka-Vogel理论的应用

Full macroscopic thermalization and the formation of Schrödinger's cats by unitary time evolution in the weakly perturbed Ising model - Applications of the Roos-Sugimoto-Teufel-Tumulka-Vogel theory

本研究证明弱随机扰动的铁磁Ising模型中，典型扰动使所有初始态在宏观可观测量上热化，并在有序相周期边界下形成宏观薛定谔猫态，结合RSTTV理论与Ising大偏差估计。

Entropy for Colored Quark States at Finite Temperature

The quantum entropy at finite temperatures is analyzed by using models for colored quarks making up the physical states of the hadrons. We explicitly work out some special models for the structure of the states of SU(2) and SU(3) relating to the effects of the temperature on the quantum entropy. We show that the entropy of the singlet states monotonically decreases meaning that the mixing of these states continually diminishes with the temperature. It has been found that the structure of the octet states is more complex so that it can be best characterized by two parts. One part is very simila…

纠缠与保真度在局部扰动的拓扑码中的量子相变

Entanglement and fidelity across quantum phase transitions in locally perturbed topological codes with open boundaries

研究局部磁扰与各向异性相互作用对Kitaev码拓扑-非拓扑量子相变的影响，通过保真度和纠缠分析相变临界点及临界行为。

Bounds on universal quantum computation with perturbed 2d cluster states

Motivated by the possibility of universal quantum computation under noise perturbations, we compute the phase diagram of the 2d cluster state Hamiltonian in the presence of Ising terms and magnetic fields. Unlike in previous analysis of perturbed 2d cluster states, we find strong evidence of a very well defined cluster phase, separated from a polarized phase by a line of 1st and 2nd order transitions compatible with the 3d Ising universality class and a tricritical end point. The phase boundary sets an upper bound for the amount of perturbation in the system so that its ground state is still u…