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We investigate the quantum phase transition in the random transverse-field Ising model under the influence of Ohmic dissipation. To this end, we numerically implement a strong-disorder renormalization-group scheme. We find that Ohmic…

Strongly Correlated Electrons · Physics 2010-01-18 Thomas Vojta , J. A. Hoyos

In this paper we consider an approach, which allows researching a processes of order-disorder transition in various systems (with any distribution of the exchange integrals signs) in the frame of Ising model. A new order parameters, which…

Statistical Mechanics · Physics 2012-05-18 P. D. Andriushchenko , K. V. Nefedev

We discuss the effect of dissipation on quantum phase transitions. In particular we concentrate on the Superconductor to Insulator and Quantum-Hall to Insulator transitions. By invoking a phenomenological parameter $\alpha$ to describe the…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Aharon Kapitulnik , Nadya Mason , Steven A. Kivelson , Sudip Chakravarty

We study the quantum phase transition in the two-dimensional random Ising model in a transverse field by Monte Carlo simulations. We find results similar to those known analytically in one-dimension: the dynamical exponent is infinite and,…

Disordered Systems and Neural Networks · Physics 2016-08-31 C. Pich , A. P. Young

We consider a one-dimensional Ising model in a transverse magnetic field coupled to a dissipative heat bath. The phase diagram and the critical exponents are determined from extensive Monte Carlo simulations. It is shown that the character…

Statistical Mechanics · Physics 2007-05-23 Philipp Werner , Klaus Voelker , Matthias Troyer , Sudip Chakravarty

The ground state structure of the two-dimensional random field Ising magnet is studied using exact numerical calculations. First we show that the ferromagnetism, which exists for small system sizes, vanishes with a large excitation at a…

Disordered Systems and Neural Networks · Physics 2009-11-07 E. T. Seppälä , M. J. Alava

The interplay between disorder, quantum fluctuations and dissipation is studied in the random transverse Ising chain coupled to a dissipative Ohmic bath with a real space renormalization group. A typically very large length scale, L*, is…

Disordered Systems and Neural Networks · Physics 2007-05-23 Gregory Schehr , Heiko Rieger

The spin-1/2 quantum Ising chain in a transverse random magnetic field is studied by means of the density-matrix renormalization group. The system evolves from an ordered to a paramagnetic state as the amplitude of the random field is…

Disordered Systems and Neural Networks · Physics 2009-10-30 A. Juozapavicius , S. Caprara , A. Rosengren

Phase transitions in the three-dimensional diluted Ising antiferromagnet in an applied magnetic field are analyzed numerically. It is found that random magnetic field in a system with spin concentration below a certain threshold induces a…

Other Condensed Matter · Physics 2009-11-11 V. V. Prudnikov , V. N. Borodikhin

The dynamic magnetization-reversal phenomena in the Ising model under a finite-duration external magnetic field competing with the existing order for $T<T_c^0$ has been discussed. The nature of the phase boundary has been estimated from the…

Statistical Mechanics · Physics 2007-05-23 Arnab Chatterjee , Bikas K. Chakrabarti

We consider random extended surface perturbations in the transverse field Ising model decaying as a power of the distance from the surface towards a pure bulk system. The decay may be linked either to the evolution of the couplings or to…

Statistical Mechanics · Physics 2007-05-23 L. Turban , D. Karevski , F. Igloi

The application of a magnetic field transverse to the easy axis, Ising direction in the quasi-two-dimensional Kagome staircase magnet, Co3V2O8, induces three quantum phase transitions at low temperatures, ultimately producing a novel high…

Strongly Correlated Electrons · Physics 2015-11-10 K. Fritsch , G. Ehlers , K. C. Rule , K. Habicht , M. Ramazanoglu , H. A. Dabkowska , B. D. Gaulin

The percolation study offers valuable insights into the characteristics of phase transition, shedding light on the underlying mechanisms that govern the formation of global connectivity within the system. We explore the percolation phase…

Nuclear Theory · Physics 2025-04-02 Ranran Guo , Xiaobing Li , Rui Wang , Shiyang Chen , Yuanfang Wu , Zhiming Li

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…

Statistical Mechanics · Physics 2008-02-03 T. Nattermann

We investigate a model for randomly layered magnets, viz. a three-dimensional Ising model with planar defects. The magnetic phase transition in this system is smeared because static long-range order can develop on isolated rare spatial…

Statistical Mechanics · Physics 2007-05-23 Shellie Huether , Ryan Kinney , Thomas Vojta

In the ordered phase of the 3D Ising model, minority spin clusters are surrounded by a boundary of dual plaquettes. As the temperature is raised, these spin clusters become more numerous, and it is found that eventually their boundaries…

Statistical Mechanics · Physics 2023-05-03 Michael Grady

Traditional simulated annealing utilizes thermal fluctuations for convergence in optimization problems. Quantum tunneling provides a different mechanism for moving between states, with the potential for reduced time scales. We compare…

Condensed Matter · Physics 2007-05-23 J. Brooke , D. Bitko , T. F. Rosenbaum , G. Aeppli

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…

Statistical Mechanics · Physics 2015-12-22 Massimo Campostrini , Andrea Pelissetto , Ettore Vicari

The effect of the zero centered Gaussian random magnetic field distribution on the phase diagrams and ground state magnetizations of the transverse Ising thin film has been investigated. As a formulation, the differential operator technique…

Statistical Mechanics · Physics 2016-08-14 Ümit Akıncı

The interplay between disorder and compressibility in Ising magnets is studied. Contrary to pure systems in which a weak compressibility drives the transition first order, we find from a renormalization group analysis that it has no effect…

Condensed Matter · Physics 2015-06-25 Yonathan Shapir , Serge Galam