Quantum Physics

Effects of defects in the XY chain with frustrated boundary conditions

It has been recently proven that new types of bulk local order can ensue due to frustrated boundary condition, that is, periodic boundary conditions with an odd number of lattice sites and antiferromagnetic interactions. For the quantum XY chain in …

Asymptotic behavior of Toeplitz determinants with a delta function singularity

We find the asymptotic behaviors of Toeplitz determinants with symbols which are a sum of two contributions, one analytical and non-zero function in an annulus around the unit circle, and the other proportional to a Dirac delta function. The formulas …

Mutual information for fermionic systems

We study the behavior of the mutual information (MI) in various quadratic fermionic chains, with and without pairing terms and both with short- and long-range hoppings. The models considered include the short-range Kitaev model and also cases in …

Discerning the Nature of Neutrinos: Decoherence and Geometric Phases

We present new approaches to distinguish between Dirac and Majorana neutrinos. The first is based on the analysis of the geometric phases associated to neutrinos in matter, the second on the effects of decoherence on neutrino oscillations. In the …

Entanglement in indistinguishable particle systems

For systems consisting of distinguishable particles, there exists an agreed upon notion of entanglement which is fundamentally based on the possibility of addressing individually each one of the constituent parties. Instead, the indistinguishability …

The frustration of being odd: how boundary conditions can destroy local order

A central tenant in the classification of phases is that boundary conditions cannot affect the bulk properties of a system. In this work, we show striking, yet puzzling, evidence of a clear violation of this assumption. We use the prototypical …

Consequences of f(?) Cosmology in Thermal Leptogenesis and Gravitino Late Abundance

Thermal Leptogenesis and the gravitino problem are reviewed in the framework of non-standard cosmologies. We consider in particular the f(T) cosmology, where T is the torsion field. We constrain the parameters space of these cosmological models …

Probing quantum field theory particle mixing and dark-matter-like effects with Rydberg atoms

We analyze the oscillations of Rydberg atoms in the framework of quantum field theory and we reveal non-trivial vacuum energy which has the equation of state of the dark matter. This energy is similar to that expected for mixed neutrinos and affects …

Probing axion mediated fermion–fermion interaction by means of entanglement

We propose a new approach in the investigation and detection of axion and axion–like particles based on the study of the entanglement for two interacting fermions. We study a system made of two identical fermions with spin -1/2, and we show that …

Gravity, entanglement and CPT-symmetry violation in particle mixing

We study the probability oscillations of mixed particles in the presence of self gravitational interaction. We show that the presence of the parity leads to the violation of the time-reversal symmetry while the CP-symmetry is preserved hence inducing …