We analyze the onset of classical behaviour after a second-order phase transition in quantum field theory. We consider a scalar theory in which the system-field interacts with its environment, represented both by further scalar fields and by its own short-wavelength modes. We compute the decoherence time for the system-field modes and compare it with the other time scales of the model. Within our approximations we see that the long-wavelength modes have decohered by the time that the transition has been first implemented (the spinodal time)We analyze the onset of classical behaviour after a second-order phase transition in quantum field theory. We consider a scalar theory in which the system-field interacts with its environment, represented both by further scalar fields and by its own short-wavelength modes. We compute the decoherence time for the system-field modes and compare it with the other time scales of the model. Within our approximations we see that the long-wavelength modes have decohered by the time that the transition has been first implemented (the spinodal time)

Feb 13, 20010 citations

Memories of quenches in operator mixing

Joydeep Chakrabortty, Diptarka Das, Bidyut Dey +2 more

We work perturbatively with an interacting quantum field theory comprised of two distinct scalar fields. In this theory, we introduce a sudden quench of the mass of one of the scalars at time ${t}_{0}$ . Also, the quartic interaction between the two scalars is turned on at time ${t}_{\mathrm{in}}$ . These break time-translation invariance. In this setup we examine the effects of the relative ordering of ${t}_{0}$ and ${t}_{\mathrm{in}}$ on composite operator mixing. We study how such operator mixing affects features of the scalar potential. We find that the late time effective potential can be sensitive enough to the quenches to trigger phase transitions.We work perturbatively with an interacting quantum field theory comprised of two distinct scalar fields. In this theory, we introduce a sudden quench of the mass of one of the scalars at time ${t}_{0}$. Also, the quartic interaction between the two scalars is turned on at time ${t}_{\mathrm{in}}$. These break time-translation invariance. In this setup we examine the effects of the relative ordering of ${t}_{0}$ and ${t}_{\mathrm{in}}$ on composite operator mixing. We study how such operator mixing affects features of the scalar potential. We find that the late time effective potential can be sensitive enough to the quenches to trigger phase transitions.

arXiv:2208.01064Physical review. D/Physical review. D.Nov 14, 20220 citations

Quantum field theory for nonequilibrium phase transitions

Sang Pyo Kim

Springer eBooksJun 25, 20060 citations

Adiabatic Quantum Computation and the Theory of Quantum Phase Transitions

William M. Kaminsky, Seth Lloyd

Bulletin of the American Physical SocietyMar 8, 20070 citations

HOT SCALAR THEORY IN LARGE N: BOSE-EINSTEIN CONDENSATION ∗

Peter Arnold, Boris Tom, Á Sik

I review the Bose-Einstein condensation phase transition of dilute gases of cold atoms, for particle theorists acquainted with methods of field theory at finite temperature. I then discuss how the dependence of the phase transition temperature on the interaction strength can be computed in the large N approximation. 1 Phase Transitions in Hot Scalar Theories The standard example from particle physics of a scalar theory is the Higgs sector of electroweak theory, which has a phase transition (or a crossover) at a temperature of order the weak scale: say, a few hundred GeV or so. Let’s focus on pure scalar theory by imagining setting the gauge coupling constant gw to zero. At finite temperature, the Higgs picks up a thermal contribution #λT 2 to its effective mass, and the effective potential becomes roughly of the form V (φ) ∼ m 2 eff (T)φ2 + λφ 4 with m 2 eff (T) = −M2 + #λT 2. At sufficiently high temperature, the #λT 2 turns the potential from being concave down at the origin to concave up, and so restores the symmetry that is spontaneously broken at zero temperature.I review the Bose-Einstein condensation phase transition of dilute gases of cold atoms, for particle theorists acquainted with methods of field theory at finite temperature. I then discuss how the dependence of the phase transition temperature on the interaction strength can be computed in the large N approximation. 1 Phase Transitions in Hot Scalar Theories The standard example from particle physics of a scalar theory is the Higgs sector of electroweak theory, which has a phase transition (or a crossover) at a temperature of order the weak scale: say, a few hundred GeV or so. Let’s focus on pure scalar theory by imagining setting the gauge coupling constant gw to zero. At finite temperature, the Higgs picks up a thermal contribution #λT 2 to its effective mass, and the effective potential becomes roughly of the form V (φ) ∼ m 2 eff (T)φ2 + λφ 4 with m 2 eff (T) = −M2 + #λT 2. At sufficiently high temperature, the #λT 2 turns the potential from being concave down at the origin to concave up, and so restores the symmetry that is spontaneously broken at zero temperature.

Jan 1, 20000 citations

We work perturbatively with an interacting quantum field theory comprised of two distinct scalar fields. In this theory, we introduce a sudden quench of the mass of one of the scalars at time

{t}_{0}

. Also, the quartic interaction between the two scalars is turned on at time

{t}_{\mathrm{in}}

. These break time-translation invariance. In this setup we examine the effects of the relative ordering of

{t}_{0}

and

{t}_{\mathrm{in}}

on composite operator mixing. We study how such operator mixing affects features of the scalar potential. We find that the late time effective potential can be sensitive enough to the quenches to trigger phase transitions.