The laws of thermodynamics put limits to the efficiencies of thermal machines. Analogues of these laws are now established for quantum engines weakly and passively coupled to the environment providing a framework to find improvements to their performance. Systems whose interaction with the environment is actively controlled do not fall in that framework. Here we consider systems actively and lo...

The Bethe ansatz equations for the spin 1/2 Heisenberg XXZ spin chain are numerically solved, and the energy eigenvalues are determined for the anti-ferromagnetic case. We examine the relation between the XXZ spin chain and the Thirring model, and show that the spectrum of the XXZ spin chain is different from that of the regularized Thirring model.

In a recent Letter Hamacher, Stolze, and Wenzel [1] studied the disordered spin-1=2 antiferromagnetic XXZ chain H ˆ J X Lÿ1 iˆ1 ‰ i …S x i S x i‡1 ‡ S y i S y i‡1 † ‡ S z i S z i‡1 Š (1) with i independent identically distributed random variables uniformly distributed over the interval ‰1 ÿ W; 1 ‡ WŠ, with the parameter W controlling the strength of the disorder. The authors claim that for < 1 ...

In the framework of quantum groups and additive R-matrices, the fusion procedure allows to construct higher-dimensional solutions of the Yang-Baxter equation. These solutions lead to integrable one-dimensional spin-chain Hamiltonians. Here fusion is shown to generalize naturally to non-additive R-matrices, which therefore do not have a quantum group symmetry. This method is then applied to the ...

We study thermal correlation functions of the one-dimensional impenetrable lattice anyons. These can be presented as a difference two Fredholm determinants. To describe large-time and long-distance behavior these objects, we use effective form-factor approach. The asymptotic is different in spacelike timelike regions. In particular, region observe additional power factor on top exponential deca...

in this paper, lagrangian and equations describing one-dimensional anisotropic non-heisenberg model are studied. in this study we used the generalized coherent states in real parametrizations and the feynman path integral for these states in su(3) group. these equations describe nonlinear dynamics of non-heisenberg ferromagnetic chain completely. solutions of these equations are magnetic solito...

We consider a model arising in facilitated Rydberg chains with positional disorder which features Hilbert space the topology of $d$-dimensional hypercube. This allows for straightforward interpretation many-body dynamics terms single particle one on and provides an explicit link between scars. Exploiting this perspective, we show that integrability-breaking enhances scars followed by inhibition...

The entanglement at zero-temperature is studied in a two-qubit XZ spin-1/2 chain model in anexternal magnetic field which is applied in the z direction. We have obtained an analytical relation forthe effect of the external magnetic field on the concurrence. It is shown that the ground state of thesystem depends on the strength of exchange coupling. We have shown that the analytical relation oft...