Related papers: Dissipation effects in percolating quantum Ising m…
In the present paper, we theoretically study the effect of density of state variation on the phenomena in the discontinuous magnetic field. Special attention is paid to the transient processes when the magnetic field is switched on (off).…
A general condition for sharp transition of decay rate from quantum to thermal regimes is derived in dissipative tunneling models when position dependent mass is involved. It is shown that the effect of dissipation in general changes the…
We investigate the magnetic properties of small transition metal clusters using a simple statistical model, which requires some input data from ab initio spin-density functional calculations. In our study we consider a thermodynamically…
The nature of the zero temperature ordering transition in the 3D Gaussian random field Ising magnet is studied numerically, aided by scaling analyses. In the ferromagnetic phase the scaling of the roughness of the domain walls, $w\sim…
The effect of the random magnetic field distribution on the phase diagrams and ground state magnetizations of the Ising nanowire has been investigated with effective field theory with correlations. Gaussian distribution has been chosen as a…
In a recent work, Le Hur has shown that dissipative coupling to gate electrodes may play an important role in a quantum box near its degeneracy point [K. Le Hur, Phys. Rev. Lett. {\bf 92}, 196804 (2004)]: While quantum fluctuations of the…
Spin-crossover compounds, which are characterized by magnetic ions showing low-spin and high-spin states at thermally accessible energies, are ubiquitous in nature. We here focus on the effect of an exchange interaction on the collective…
By means of the discrete truncated Wigner approximation we study dynamical phase transitions arising in the steady state of transverse-field Ising models after a quantum quench. Starting from a fully polarized ferromagnetic initial…
We theoretically investigate impurity correlation and magnetic clustering effects on the long-range ferromagnetic ordering in diluted magnetic semiconductors, such as $\textrm{Ga}_{1-x}\textrm{Mn}_{x}\textrm{As}$, using analytical arguments…
Using cold bosonic atoms with two (hyperfine) ground states, we introduce a spin-boson mixture which allows to implement the quantum Ising model in a tunable dissipative environment. The first specie lies in a deep optical lattice with…
The two-dimensional (zero magnetic field) Ising model is known to undergo a second order para-ferromagnetic phase transition, which is accompanied by a correlated percolation transition for the Fortuin-Kasteleyn (FK) clusters. In this paper…
We study the evolution of nearest-neighbor entanglement in the one dimensional Ising model with an external transverse field. The system is initialized as the so called "thermal ground state" of the pure Ising model. We analyze properties…
The magnetic analog of the Gr\"{u}neisen parameter, i.e., the magnetocaloric effect, is a valuable tool for studying field-tuned quantum phase transitions. We determine the magnetic Gr\"{u}neisen parameter of the one-dimensional random…
The quantum transport in a narrow channel (NC) is studied in the presence of a time-dependent delta-profile electric field. The electric field is taken to be transversely polarized, with frequency $\omega$, causing inter-subband and…
We present a detailed study of the finite one-dimensional quantum Ising chain in a transverse field in the presence of boundary magnetic fields coupled with the order-parameter spin operator. We consider two magnetic fields located at the…
We simulate the dc magnetic response of the diluted dipolar-coupled Ising magnet LiHo\(_{0.045}\)Y\(_{0.955}\)F\(_4\) in a transverse field, using exact diagonalization of a two-spin Hamiltonian averaged over nearest-neighbour…
We employ an effective-field theory with correlations in order to study the phase diagram and ground-state magnetizations of a selectively diluted Ising antiferromagnet on triangular and honeycomb lattices. Dilution of different sublattices…
A review is given on some recent developments in the theory of the Ising model in a random field. This model is a good representation of a large number of impure materials. After a short repetition of earlier arguments, which prove the…
The thermodynamics of randomly quenched disordered Ising metamagnet has been studied by Monte Carlo simulations. The disorder has been implemented either by inserting nonmagnetic impurity or by uniformly distributed quenched random magnetic…
We examine the low frequency spin susceptibility of the paramagnetic phase of the quantum Ising chain in transverse field at temperatures well below the energy gap. We find that the imaginary part is dominated by rare quantum processes in…