scholarly journals Nonequilibrium-relaxation approach to quantum phase transitions: Nontrivial critical relaxation in cluster-update quantum Monte Carlo

2020 ◽  
Vol 101 (3) ◽  
Author(s):  
Yoshihiko Nonomura ◽  
Yusuke Tomita
Keyword(s):  
Monte Carlo ◽  
Phase Transitions ◽  
Quantum Monte Carlo ◽  
Quantum Phase Transitions ◽  
Quantum Phase

scholarly journals MICROSCOPIC CALCULATIONS OF QUANTUM PHASE TRANSITIONS IN FRUSTRATED MAGNETIC LATTICES

2006 ◽  
Vol 20 (19) ◽  
pp. 2612-2623
Author(s):  
RAYMOND F. BISHOP ◽  
SVEN E. KRÜGER
Keyword(s):  
Phase Transitions ◽  
Quantum Monte Carlo ◽  
Quantum Phase Transitions ◽  
Quantum Phase ◽  
Cluster Method ◽  
Many Body ◽  
Many Body Theory ◽  
Body Theory ◽  
Quantum Monte Carlo Simulations ◽  
Spatial Continuum

It is nowadays acknowledged that the coupled cluster method (CCM) provides one of the most powerful and most widely used of all ab initio techniques of microscopic quantum many-body theory. It has been applied to a broad range of both finite and extended physical systems defined on a spatial continuum, where it has generally yielded numerical results which are among the most accurate available. This widespread success has spurred many recent applications to quantum systems defined on a lattice. We discuss here a typical example of a two-dimensional spin-half Heisenberg magnet with two kinds of competing nearest-neighbour bonds. We show how the CCM can successfully describe the influence of strong quantum fluctuations on the zero-temperature phases and their quantum phase transitions. The model shows how the CCM can successfully describe the effects of competition between magnetic bonds with and without the presence of frustration. The frustrated case is particulary important since many other methods, including quantum Monte Carlo simulations, typically fail in this regime.

scholarly journals Quantum phase transitions in the spin-boson model: Monte Carlo method versus variational approach à la Feynman

2020 ◽  
Vol 101 (18) ◽  
Author(s):  
G. De Filippis ◽  
A. de Candia ◽  
L. M. Cangemi ◽  
M. Sassetti ◽  
R. Fazio ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Phase Transitions ◽  
Monte Carlo Method ◽  
Variational Approach ◽  
Quantum Phase Transitions ◽  
Quantum Phase ◽  
Boson Model

scholarly journals Quantum phase transitions on the hexagonal lattice

2021 ◽  
pp. 2141003
Author(s):  
Dominik Smith ◽  
Pavel Buividovich ◽  
Michael Körner ◽  
Maksim Ulybyshev ◽  
Lorenz von Smekal
Keyword(s):  
Monte Carlo ◽  
Phase Transitions ◽  
Monte Carlo Simulations ◽  
First Principles ◽  
Present Status ◽  
Phase Structure ◽  
Quantum Phase Transitions ◽  
Hexagonal Lattice ◽  
Quantum Phase ◽  
Hybrid Monte Carlo

Hubbard-type models on the hexagonal lattice are of great interest, as they provide realistic descriptions of graphene and other related materials. Hybrid Monte Carlo simulations offer a first-principles approach to study their phase structure. Here, we review the present status of our work in this direction.

Quantum phase transitions

2004 ◽  
Vol 174 (8) ◽  
pp. 853 ◽  
Author(s):  
Sergei M. Stishov
Keyword(s):  
Phase Transitions ◽  
Quantum Phase Transitions ◽  
Quantum Phase

scholarly journals Magnetic Field- and Pressure-Induced Quantum Phase Transitions in NH4CuCl3

2005 ◽  
Vol 159 ◽  
pp. 241-245 ◽  
Author(s):  
Masashi Fujisawa ◽  
Budhy Kurniawan ◽  
Toshio Ono ◽  
Hidekazu Tanaka
Keyword(s):  
Magnetic Field ◽  
Phase Transitions ◽  
Quantum Phase Transitions ◽  
Quantum Phase

scholarly journals Interaction between Different Kinds of Quantum Phase Transitions

2021 ◽  
Vol 3 (2) ◽  
pp. 253-261
Author(s):  
Angel Ricardo Plastino ◽  
Gustavo Luis Ferri ◽  
Angelo Plastino
Keyword(s):  
Phase Transitions ◽  
Nuclear Physics ◽  
Body Problem ◽  
Quantum Phase Transitions ◽  
Quantum Phase ◽  
Exactly Solvable Models ◽  
Solvable Models ◽  
Many Body ◽  
Pairing Interaction ◽  
Exactly Solvable

We employ two different Lipkin-like, exactly solvable models so as to display features of the competition between different fermion–fermion quantum interactions (at finite temperatures). One of our two interactions mimics the pairing interaction responsible for superconductivity. The other interaction is a monopole one that resembles the so-called quadrupole one, much used in nuclear physics as a residual interaction. The pairing versus monopole effects here observed afford for some interesting insights into the intricacies of the quantum many body problem, in particular with regards to so-called quantum phase transitions (strictly, level crossings).

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