scholarly journals Mean-field quantum phase transition in graphene and in general gapless systems

2010 ◽  
Vol 82 (15) ◽  
Author(s):  
Ádám Bácsi ◽  
Attila Virosztek ◽  
László Borda ◽  
Balázs Dóra
Keyword(s):  
Phase Transition ◽  
Quantum Phase Transition ◽  
Mean Field ◽  
Quantum Phase

scholarly journals Classical and Quantum Signatures of Quantum Phase Transitions in a (Pseudo) Relativistic Many-Body System

2020 ◽  
Vol 5 (2) ◽  
pp. 26
Author(s):  
Maximilian Nitsch ◽  
Benjamin Geiger ◽  
Klaus Richter ◽  
Juan-Diego Urbina
Keyword(s):  
Phase Transition ◽  
Quantum Phase Transition ◽  
Quantum Phase Transitions ◽  
Mean Field ◽  
Finite Size ◽  
Quantum Phase ◽  
Effective Model ◽  
Field Analysis ◽  
Many Body ◽  
Linear Dispersion

We identify a (pseudo) relativistic spin-dependent analogue of the celebrated quantum phase transition driven by the formation of a bright soliton in attractive one-dimensional bosonic gases. In this new scenario, due to the simultaneous existence of the linear dispersion and the bosonic nature of the system, special care must be taken with the choice of energy region where the transition takes place. Still, due to a crucial adiabatic separation of scales, and identified through extensive numerical diagonalization, a suitable effective model describing the transition is found. The corresponding mean-field analysis based on this effective model provides accurate predictions for the location of the quantum phase transition when compared against extensive numerical simulations. Furthermore, we numerically investigate the dynamical exponents characterizing the approach from its finite-size precursors to the sharp quantum phase transition in the thermodynamic limit.

scholarly journals On the nature of the shape coexistence and the quantum phase transition phenomena: lead region and Zr isotopes

2018 ◽  
Vol 178 ◽  
pp. 05005
Author(s):  
José-Enrique García-Ramos ◽  
Kris Heyde
Keyword(s):  
Phase Transition ◽  
Quantum Phase Transition ◽  
Rapid Change ◽  
Mean Field ◽  
Quantum Phase ◽  
Ground State Structure ◽  
Shape Coexistence ◽  
State Structure ◽  
The Mean ◽  
Isotope Chain

The goal of this contribution is to analyze the connection between shape coexistence and quantum phase transition, two seemingly unrelated phenomena that share common aspects, namely, the rapid change in the ground state structure along an isotope chain or the presence of several minima at the mean-field level. To illustrate the similarities and differences between both phenomena, we will focus in the Pb region, in particular in Pt and Hg isotopes, as well as in Zr isotopes.

scholarly journals Adiabatic quenches and characterization of amplitude excitations in a continuous quantum phase transition

2016 ◽  
Vol 113 (34) ◽  
pp. 9475-9479 ◽  
Author(s):  
Thai M. Hoang ◽  
Hebbe M. Bharath ◽  
Matthew J. Boguslawski ◽  
Martin Anquez ◽  
Bryce A. Robbins ◽  
...  
Keyword(s):  
Phase Transition ◽  
Quantum Phase Transition ◽  
Energy Gap ◽  
Quantum Critical Point ◽  
Mean Field ◽  
Finite Size ◽  
Quantum Phase ◽  
Nonequilibrium Dynamics ◽  
Many Body ◽  
Goldstone Modes

Spontaneous symmetry breaking occurs in a physical system whenever the ground state does not share the symmetry of the underlying theory, e.g., the Hamiltonian. This mechanism gives rise to massless Nambu–Goldstone modes and massive Anderson–Higgs modes. These modes provide a fundamental understanding of matter in the Universe and appear as collective phase or amplitude excitations of an order parameter in a many-body system. The amplitude excitation plays a crucial role in determining the critical exponents governing universal nonequilibrium dynamics in the Kibble–Zurek mechanism (KZM). Here, we characterize the amplitude excitations in a spin-1 condensate and measure the energy gap for different phases of the quantum phase transition. At the quantum critical point of the transition, finite-size effects lead to a nonzero gap. Our measurements are consistent with this prediction, and furthermore, we demonstrate an adiabatic quench through the phase transition, which is forbidden at the mean field level. This work paves the way toward generating entanglement through an adiabatic phase transition.

scholarly journals Reply to “Comment on ‘Quantum phase transition in the four-spin exchange antiferromagnet’ ”

2010 ◽  
Vol 82 (13) ◽  
Author(s):  
Valeri N. Kotov ◽  
D. X. Yao ◽  
A. H. Castro Neto ◽  
D. K. Campbell
Keyword(s):  
Phase Transition ◽  
Quantum Phase Transition ◽  
Spin Exchange ◽  
Quantum Phase

scholarly journals Superfluid–Mott-insulator quantum phase transition of light in a two-mode cavity array with ultrastrong coupling

2017 ◽  
Vol 95 (3) ◽  
Author(s):  
Jingtao Fan ◽  
Yuanwei Zhang ◽  
Lirong Wang ◽  
Feng Mei ◽  
Gang Chen ◽  
...  
Keyword(s):  
Phase Transition ◽  
Quantum Phase Transition ◽  
Mott Insulator ◽  
Quantum Phase ◽  
Cavity Array
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