Related papers: Fermionic S-matrix and cosmological correlators: T…
We construct a perturbative S-matrix for interacting massive scalar fields in global de Sitter space. Our S-matrix is formulated in terms of asymptotic particle states in the far past and future, taking appropriate care for light fields…
Extending scattering to states with unphysical mass values (particles ``off their mass shell'') has been instrumental in developing modern amplitude technology for Minkowski spacetime. Here, we study the off-shell correlators which underpin…
An increasing number of experiments at the Belle, BNL, CERN, DA{\Phi}NE and SLAC accelerators are confirming the violation of time reversal invariance (T). The violation signifies a fundamental asymmetry between the past and future and…
We investigate the preservation of unitarity in a Lorentz and CPT-violating QED model containing higher-order operators. In particular, we consider modifications in the fermion sector with dimension-five operators. The higher-order…
We define an $S$-matrix for massive scalar fields on a fixed de Sitter spacetime, in the expanding patch co-ordinates relevant for early Universe cosmology. It enjoys many of the same properties as its Minkowski counterpart, for instance:…
Anti-de Sitter spacetime and the static patch of de Sitter spacetime are arenas for investigating thermal and finite-size effects seen by an accelerated quantum observer. We consider an Unruh-DeWitt detector in uniform circular motion…
We define a perturbative S-matrix in a local patch of de Sitter background in the limit when the curvature length scale ($\ell$) is large and study the 'soft' behavior of the scalar QED amplitudes in de Sitter spacetime in generic…
We propose a new experiment to search for a time-reversal (T) symmetry breaking process in muon decay and the Majoranality of the neutrinos. In the presence of V+A interactions, the Majoranality appears as a T-violating term in the muon…
The violation of the Bell inequality for Dirac fermions is investigated in the cosmological de Sitter spacetime, in the presence of background electromagnetic fields of constant strengths. The orthonormal Dirac mode functions are obtained…
We study fermionic bulk fields in the dS/CFT dualities relating ${\cal N}=2$ supersymmetric Euclidean vector models with reversed spin-statistics in three dimensions to supersymmetric Vasiliev theories in four-dimensional de Sitter space.…
In three spatial dimensions, in the unitary limit of a non-relativistic quantum Bose or Fermi gas, the scattering length diverges. This occurs at a renormalization group fixed point, thus these systems present interesting examples of…
A no-go theorem for parity-violation in even $D$-dimensional spacetimes invariant under $ISO(d)$ and dilatations (as well as the implications for odd $D$) is derived. For the case of real massless scalar and gravitons (as well as any…
S-matrix is one of the fundamental observables of the quantum theory of relativistic particles. There have been attempts to understand the quantum dynamics of relativistic particles abstractly in terms of S-matrix bypassing a Lagrangian…
In this paper we bootstrap de Sitter wavefunction coefficients (WFCs) involving fermionic operators. Starting with a fixed total-energy pole order, we systematically impose the conformal Ward identities (CWI) together with cutting-rule…
The origin of the large CP-odd and T-odd asymmetry observed in the decay K_L -> pi^+ pi^- e^+ e^- is traced to the polarization properties of the photon in the decay K_L -> pi^+ pi^- gamma. The Stokes vector of the photon S = (S_1, S_2,…
We examine the T-odd transverse lepton and $\Lambda$ polarizations in the baryonic decays of $\Lambda_b\to\Lambda l^+l^- (l=e ,\mu)$ to study the T violating effects. We show that the lepton polarizations are suppressed but the $\Lambda$…
We provide a general analysis of time reversal invariance violation in the exclusive semileptonic B decays B to D l nu and B to D* l nu. Measurements of the lepton and D* polarizations can be used to search for and identify non-standard…
We study the Dirac oscillator for spin-1/2 particles in a spacetime containing a spinning cosmic string endowed with both curvature (disclination) and torsion (screw dislocation). The background geometry includes off-diagonal and is…
In this work, we study quantum fluctuations in the stress energy tensor of spinor fields evolving in general FRW spacetimes. We quantify these fluctuations by the noise kernel of spinor fields. For the particular case of de Sitter…
We study the relation between two sets of correlators in interacting quantum field theory on de Sitter space. The first are correlators computed using in-in perturbation theory in the expanding cosmological patch of de Sitter space (also…