It has recently been argued that if spacetime $\mathcal{M}$ possesses nontrivial structure at small scales, an appropriate semiclassical description of it should be based on nonlocal bitensors instead local tensors such as the metric ${g}_{ab}(p)$. Two most relevant in this context are Synge's world function $\mathrm{\ensuremath{\Omega}}(p,{p}_{0})$ and van Vleck determinant (VVD) $\mathrm{\ensuremath{\Delta}}(p,{p}_{0})$, they encode properties (de)focusing behavior geodesics. They also...

We investigate the transition probability rate of a Unruh-DeWitt (UD) detector interacting with massless scalar field for finite duration proper time, $T$, detector. For UD moving at uniform acceleration, $a$, we explicitly show that finite-time can be written as sum purely thermal terms, and non-thermal transient terms. While terms are independent depend on $(\Delta ET)$, $(aT)$, E/a)$, where $\Delta E$ is energy gap Particularly, oscillatory respect to variable so they may averaged out...

One of the primary reasons behind difficulty in observing Unruh effect is that for achievable acceleration scales finite temperature effects are significant only low frequency modes field. Since density field falls small frequencies free space, which relevant thermal would be less number to make an observably effect. In this Letter, we investigate response Unruh-DeWitt detector coupled a massless scalar confined long cylindrical cavity. The inside such cavity shows resonance structure, i.e.,...

Despite numerous proposals investigating various properties of accelerated detectors in different settings, detecting the Unruh effect remains challenging due to typically weak signal at achievable accelerations. For an atom with frequency gap <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msub><a:mi>ω</a:mi><a:mn>0</a:mn></a:msub></a:math>, free space, significant acceleration-induced modification like transition rates and radiative energy shifts requires...

Assuming that high energy effects may alter the standard dispersion relations governing quantized fields, influence of such modifications on various phenomena has been studied extensively in literature. In different contexts, it generally found that, while super-luminal hardly affect results, sub-luminal can lead to (even substantial) conventional results. A polymer scalar field is characterized by a series modified along with suitable changes measure density modes. Amongst relations, one...

We investigate the random motion of a mirror in (1 + 1)-dimensions that is immersed thermal bath massless scalar particles which are interacting with through boundary condition. Imposing Dirichlet or Neumann conditions on moving mirror, we evaluate mean radiation reaction force and correlation function describing fluctuations about value. From thus obtained, explicitly establish fluctuation-dissipation theorem governing mirror. Using theorem, compute mean-squared displacement at finite zero...

We investigate the observable consequences of Planck scale effects in advanced gravitational-wave detector by polymer quantizing optical field arms interferometer. For large values energy scale, compared to frequency photon interferometer arms, we consider be a collection infinite decoupled harmonic oscillators and construct new set approximated polymer-modified creation annihilation operators quantize field. Employing these operators, obtain fluctuations radiation pressure on end mirrors...

The perturbations in the early universe are generated as a result of interplay between quantum field theory and gravitation. Since these primordial lead to anisotropies cosmic microwave background eventually inhomogeneities Large Scale Structure (LSS), they provide unique opportunity probe issues which fundamental our understanding physics One such issue that remains be satisfactorily addressed is transition from their origins LSS can characterized completely terms classical quantities....

In treatments of electromagnetism, it is often tacitly assumed that the vector potentials field and their conjugate momenta satisfy canonical Poisson bracket relations, despite fact components potential are constrained by gauge conditions. Here I explicate how this comes about imposing relations on independent variables remaining after Lorenz constraint accounted for. The naively brackets happens to be correct even fixing, owing a conspiracy between conditions principle relativity.