Critical behaviour of an effective relativistic mean field model in the presence of magnetic background and boundaries

Domain boundaries, Goldstone bosons and gravitational waves

The dynamical behaviour of domain boundaries between different realizations of the vacuum of scalar fields with spontaneously broken phases is investigated. They correspond to zero-modes of the Goldstone fields, moving with the speed of light, and turn out to be accompanied by strongly oscillating gravitational fields. In certain space-time topologies this leads to a quantization condition for the symmetry breaking scale in terms of the Planck mass.

无守恒荷相对论流体的热边界

Thermal boundaries for relativistic fluids without a conserved charge

本研究针对无守恒荷的超相对论流体，推导其流体动力学场的有效边界条件，证明初边值问题适定，并发现温差下流体形成定常流的特性。

反射边界中的准周期相对论壳层：黑洞形成的可能性有多大？

Quasi-periodic relativistic shells in reflecting boundaries: How likely are black holes to form?

研究受限反射边界中两个同心壳层的引力系统，数值和解析分析表明，即使收缩壳层接近黑洞，能量转移可维持稳定周期运动，且零壳层可通过递推方程精确描述。

Turbulent flows for relativistic conformal fluids in 2+1 dimensions

We demonstrate that relativistic conformal hydrodynamics in 2+1 dimensions displays a turbulent behaviour which cascades energy to longer wavelengths on both flat and spherical manifolds. Our motivation for this study is to understand the implications for gravitational solutions through the AdS/CFT correspondence. The observed behaviour implies gravitational perturbations of the corresponding black brane/black hole spacetimes (for sufficiently large scales/temperatures) will display a similar cascade towards longer wavelengths.

Boundary S-matrix for the Integrable q-Potts Model

The 2D off-critical q-state Potts model with boundaries was studied as a factorizable relativistic scattering theory. The scattering S-matrices for particles reflecting off the boundaries were obtained for the cases of ``fixed'' and ``free'' boundary conditions. In the Ising limit, the computed results agreed with recent work[5].

From Defects to Boundaries

In this paper we describe how relativistic field theories containing defects are equivalent to a class of boundary field theories. As a consequence previously derived results for boundaries can be directly applied to defects, these results include reduction formulas, the Coleman-Thun mechanism and Cutcosky rules. For integrable theories the defect crossing unitarity equation can be derived and defect operator found. For a generic purely transmitting impurity we use the boundary bootstrap method to obtain solutions of the defect Yang-Baxter equation. The groundstate energy on the strip with def…

Bouncing cosmological model with general relativistic hydrodynamics in extended gravity

In this paper, in an extended theory of gravity, we have presented bouncing cosmological model at the backdrop of an isotropic, homogeneous space-time, in presence of general relativistic hydrodynamics (GRH). The scale factor has been chosen in such a manner that with appropriate normalization, the quintom bouncing scenario can be assessed. Accordingly, the bounce occurs at $t=0$ and the corresponding Hubble parameter vanishes at the bounce epoch. The equation of state (EoS) parameter and the energy conditions of the model have been analysed. The violation of strong energy condition further su…

A (1+3) Relativistic Harmonic Oscillator Simulated by an Anti-de Sitter Background

It is shown that a static $(1+3)$ anti-de Sitter metric defines, in a natural way, a relativistic harmonic oscillator in Minkowski space. The quantum theory can be solved exactly and leads to wave functions having a significantly different behaviour with respect to the non-relativistic ones. The energy spectrum coincides, up to the ground state energy, with that of the non-relativistic oscillator.

Relativistic Hydrodynamics: A Singulant Perspective

There is growing evidence that the hydrodynamic gradient expansion is factorially divergent. We advocate for using Dingle's singulants as a way to gain analytic control over its large-order behaviour for nonlinear flows. Within our approach, singulants can be viewed as new emergent degrees of freedom which reorganise the large-order gradient expansion. We work out the physics of singulants for longitudinal flows, where they obey simple evolution equations which we compute in Müller-Israel-Stewart-like models, holography and kinetic theory. These equations determine the dynamics of the large-or…

Critical Behaviour of a Homogeneous Bose Gas at Finite Temperature

A homogeneous non-relativistic Bose gas is investigated at finite temperature using renormalization group methods. The phase transition is shown to be second order and the effective chemical potential and the effective quartic coupling vanish at the critical temperature. We obtain the critical exponent $ν=0.73$ at leading order in the derivative expansion.

Quantum behaviour near a spacelike boundary in the c=1 matrix model

Certain time dependent configurations in the c=1 matrix model correspond to string theory backgrounds which have spacelike boundaries and appear geodesically incomplete. We investigate quantum mechanical properties of a class of such configurations in the matrix model, in terms of fermionic eigenvalues. We describe Hamiltonian evolution of the eigenvalue density using several different time variables, some of which are infinite and some of which are finite in extent. We derive unitary transformations relating these different descriptions, and use those to calculate fermion correlators in the t…

时空边界不破坏微分和规范对称性

Spacetime boundaries do not break diffeomorphism and gauge symmetries

本文通过Dressing Field方法证明时空边界不破坏微分和规范对称性，揭示物理区域与边界的相互定义关系。

多个反射边界能否增强纠缠提取？

Are multiple reflecting boundaries capable of enhancing entanglement harvesting?

本研究探讨两个反射边界对均匀加速Unruh-DeWitt探测器间纠缠提取的影响，发现边界可抑制或增强纠缠，适当参数选择可提升纠缠量。