Ginzburg-Landau Theory to the Phase Transitions of Ultracold Bose Gases in Disordered Optical Lattices

AbstractSpontaneous C4-symmetry breaking phases are ubiquitous in layered quantum materials, and often compete with other phases such as superconductivity. Preferential suppression of the symmetry broken phases by light has been used to explain non-equilibrium light induced superconductivity, metallicity, and the creation of metastable states. Key to understanding how these phases emerge is understanding how C4 symmetry is restored. A leading approach is based on time-dependent Ginzburg-Landau theory, which explains the coherence response seen in many systems. However, we show that, for the case of the single layered manganite La0.5Sr1.5MnO4, the theory fails. Instead, we find an ultrafast inhomogeneous disordering transition in which the mean-field order parameter no longer reflects the atomic-scale state of the system. Our results suggest that disorder may be common to light-induced phase transitions, and methods beyond the mean-field are necessary for understanding and manipulating photoinduced phases.

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Spontaneous symmetry breaking in the late Universe and glimpses of the early Universe phase transitions à la baryogenesis

International Journal of Modern Physics D ◽

10.1142/s0218271821300056 ◽

2021 ◽

Author(s):

M. Sami ◽

Radouane Gannouji

Keyword(s):

Phase Transition ◽

Phase Transitions ◽

Symmetry Breaking ◽

Spontaneous Symmetry Breaking ◽

Particle Physics ◽

Landau Theory ◽

Bubble Nucleation ◽

Beyond The Standard Model ◽

Electroweak Phase Transition ◽

Ginzburg Landau

Spontaneous symmetry breaking is the foundation of electroweak unification and serves as an integral part of the model building beyond the standard model of particle physics and it also finds interesting applications in the late Universe. We review development related to obtaining the late cosmic acceleration from spontaneous symmetry breaking in the Universe at large scales. This phenomenon is best understood through Ginzburg–Landau theory of phase transitions which we briefly describe. Hereafter, we present elements of spontaneous symmetry breaking in relativistic field theory. We then discuss the “symmetron” scenario-based upon symmetry breaking in the late Universe which is realized by using a specific form of conformal coupling. However, the model is faced with “NO GO” for late-time acceleration due to local gravity constraints. We argue that the problem can be circumvented by using the massless [Formula: see text] theory coupled to massive neutrino matter. As for the early Universe, spontaneous symmetry breaking finds its interesting applications in the study of electroweak phase transition. To this effect, we first discuss in detail the Ginzburg–Landau theory of first-order phase transitions and then apply it to electroweak phase transition including technical discussions on bubble nucleation and sphaleron transitions. We provide a pedagogical exposition of dynamics of electroweak phase transition and emphasize the need to go beyond the standard model of particle physics for addressing the baryogenesis problem. Review ends with a brief discussion on Affleck–Dine mechanism and spontaneous baryogenesis. Appendixes include technical details on essential ingredients of baryogenesis, sphaleron solution, one-loop finite temperature effective potential and dynamics of bubble nucleation.

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Topological Frustration can modify the nature of a Quantum Phase Transition

10.21203/rs.3.rs-200255/v1 ◽

2021 ◽

Author(s):

Vanja Marić ◽

Gianpaolo Torre ◽

Fabio Franchini ◽

Salvatore Giampaolo

Keyword(s):

Phase Transition ◽

Phase Transitions ◽

Quantum Phase Transition ◽

Landau Theory ◽

Continuous Phase ◽

Quantum Systems ◽

Quantum Phase ◽

Local Order ◽

Ginzburg Landau ◽

One Dimensional

Abstract Ginzburg-Landau theory of continuous phase transitions implicitly assumes that microscopic changes are negligible in determining the thermodynamic properties of the system. In this work we provide an example that clearly contrasts with this assumption. In particular, we consider the 2-cluster-Ising model, a one-dimensional spin-1/2 system that is known to exhibit a quantum phase transition between a magnetic and a nematic phase. By imposing boundary conditions that induce topological frustration we show that local order is completely destroyed on both sides of the transition and that the two thermodynamic phases can only be characterized by string order parameters. Having proved that topological frustration is capable of altering the nature of a system's phase transition, this result is a clear challenge to current theories of phase transitions in complex quantum systems.

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