Quantum phase transitions of strongly correlated metals

In this article, we discuss several aspects of the quantum phase transition, with special emphasis on the metalinsulator transition. We start with a review of key experimental and theoretical works and then discuss how doping a system reduces the critical temperature of the overall phase transition. Although many aspects of the quantum phase transition still remain an open problem, onsiderable progress has been made in revealing the underlying physics, both theoretically and experimentally.

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Observation of generalized Kibble-Zurek mechanism across a first-order quantum phase transition in a spinor condensate

Science Advances ◽

10.1126/sciadv.aba7292 ◽

2020 ◽

Vol 6 (21) ◽

pp. eaba7292

Author(s):

L.-Y. Qiu ◽

H.-Y. Liang ◽

Y.-B. Yang ◽

H.-X. Yang ◽

T. Tian ◽

...

Keyword(s):

Phase Transition ◽

Phase Transitions ◽

Power Law ◽

Quantum Phase Transition ◽

Scaling Laws ◽

Quantum Phase Transitions ◽

Quantum Phase ◽

Polar Phase ◽

First Order ◽

Spin Excitations

The Kibble-Zurek mechanism provides a unified theory to describe the universal scaling laws in the dynamics when a system is driven through a second-order quantum phase transition. However, for first-order quantum phase transitions, the Kibble-Zurek mechanism is usually not applicable. Here, we experimentally demonstrate and theoretically analyze a power-law scaling in the dynamics of a spin-1 condensate across a first-order quantum phase transition when a system is slowly driven from a polar phase to an antiferromagnetic phase. We show that this power-law scaling can be described by a generalized Kibble-Zurek mechanism. Furthermore, by experimentally measuring the spin population, we show the power-law scaling of the temporal onset of spin excitations with respect to the quench rate, which agrees well with our numerical simulation results. Our results open the door for further exploring the generalized Kibble-Zurek mechanism to understand the dynamics across first-order quantum phase transitions.

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Fermion condensation quantum phase transition versus conventional quantum phase transitions

Physics Letters A ◽

10.1016/j.physleta.2004.06.065 ◽

2004 ◽

Vol 329 (1-2) ◽

pp. 108-115 ◽

Cited By ~ 6

Author(s):

V.R. Shaginyan ◽

J.G. Han ◽

J. Lee

Keyword(s):

Phase Transition ◽

Phase Transitions ◽

Quantum Phase Transition ◽

Quantum Phase Transitions ◽

Quantum Phase

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Spherical model and quantum phase transitions

Journal of Physics Conference Series ◽

10.1088/1742-6596/2094/2/022027 ◽

2021 ◽

Vol 2094 (2) ◽

pp. 022027

Author(s):

V N Udodov

Keyword(s):

Phase Transition ◽

Phase Transitions ◽

Critical Temperature ◽

Critical Exponents ◽

Quantum Phase Transitions ◽

Dimensional Space ◽

Spherical Model ◽

Quantum Phase ◽

Two Dimensional ◽

Epsilon Expansion

Abstract The spherical Berlin-Katz model is considered in the framework of the epsilon expansion in one-dimensional and two-dimensional space. For the two-dimensional and threedimensional cases in this model, an exact solution was previously obtained in the presence of a field, and for the two-dimensional case the critical temperature is zero, that is, a “quantum” phase transition is observed. On the other hand, the epsilon expansion of critical exponents with an arbitrary number of order parameter components is known. This approach is consistent with the scaling paradigm. Some critical exponents are found for the spherical model in one-and twodimensional space in accordance with the generalized scaling paradigm and the ideas of quantum phase transitions. A new formula is proposed for the critical heat capacity exponent, which depends on the dynamic index z, at a critical temperature equal to zero. An expression is proposed for the order of phase transition with a change in temperature (developing the approach of R. Baxter), which also depends on the z index. An interpolation formula is presented for the effective dimension of space, which is valid for both a positive critical temperature and a critical temperature equal to zero. This formula is general. Transitions with a change in the field in a spherical model at absolute zero are also considered.

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