Geometric Backreaction of Modified Quantum Vacua and Diffeomorphrisim Covariance

In this paper I have shown that squeezed modified quantum vacua have an effect on the background geometry by solving the semi-classical Einstein Field Equations in modified vacuum. The resultant geometry is similar to (anti) de Sitter spacetime. This geometry could explain the change of causal structure—speed of light—in such vacua without violating diffeomorphism covariance or causality. The superluminal propagation of photons in Casimir vacuum is deduced from the effective electromagnetic action in the resultant curved geometry. Singling between different vacua is shown not to violate causality as well when the geometric effect on the null rays is considered, causing a refraction of those rays when traveling between unbounded and modified vacua.

Quantum Curve and Bilinear Fermionic Form for the Orbifold Gromov–Witten Theory of P[r]

We construct the quantum curve for the Baker-Akhiezer function of the orbifold Gromov-Witten theory of the weighted projective line P[r].Furthermore,we deduce the explicit bilinear Fermionic formula for the(stationary)Gromov-Witten potential via the lifting operator contructed from the Baker-Akhiezer function.

Covariant spin kinetic theory I:collisionless limit

We develop a covariant kinetic theory for massive fermions in a curved spacetime and an external electromagnetic field based on quantum field theory.We derive four coupled semi-classical kinetic equations accurate to O(ℏ),which describe the transports of particle number and spin degrees of freedom.The relationship with chiral kinetic theory is discussed.As an application,we study spin polarization in the presence of finite Riemann curvature and an electromagnetic field in both local and global equilibrium states.

A massless scalar field in Robertson-Walker spacetimes:Adiabatic regularization and Green’s function

We study adiabatic regularization of a coupling massless scalar field in general spatially flat Robertson-Walker(RW)spacetimes.For the conformal coupling,the 2nd-order regularized power spectrum and 4th-order regularized stress tensor are zero,and no trace anomaly exists in general RW spacetimes.This is a new result that exceeds those found in de Sitter space.For the minimal coupling,the regularized spectra are also zero in the radiationdominant and matter-dominant stages,as well as in de Sitter space.The vanishing of these adiabatically regularized spectra is further confirmed by direct regularization of the Green's function.For a general coupling and general RW spacetimes,the regularized spectra can be negative under the conventional prescription.At a higher order of regularization,the spectra will generally become positive,but will also acquire IR divergence,which is inevitable for a massless field.To avoid the IR divergence,the inside-horizon regularization is applied.Through these procedures,nonnegative UV-and IR-convergent power spectrum and spectral energy density will eventually be achieved.

Hawking radiation of Dirac particles from soft-hairy black holes

In this paper,we study the Hawking radiation of Dirac particles via tunneling formalism from linearly supertranslated Schwarzschild black holes.We find that the radiation spectrum and the Hawking temperature remain the same as the one without soft hair.