In the spirit of Bose–Einstein condensation, we present a detailed account of the statistical description of the condensation phenomena for a Fermi–Dirac gas following the works of Born and Kothari. For bosons, while the condensed phase below a certain critical temperature, permits macroscopic occupation at the lowest energy single particle state, for fermions, due to Pauli exclusion principle,...

The effective action for the local composite operator Φ2(x) in the scalar quantum field theory with λΦ4 interaction is obtained in the expansion in two-particle-point-irreducible (2PPI) diagrams up to fiveloops. The effective potential and 2-point Green’s functions for elementary and composite fields are derived. The ground state energy as well as oneand two-particle excitations are calculated ...

Using the relation proposed by Weinberg in 1972, combining quantum and cosmological parameters, we prove that the self gravitational potential energy of any fundamental particle is a quantum, with physical properties independent of the mass of the particle. It is a universal quantum of gravitational energy, and its physical properties depend only on the cosmological scale factor R and the physi...

Lorentz violation at high energies might lead to non linear dispersion relations for the fundamental particles. We analyze observational constraints on these without assuming any a priori equality between the coefficients determining the amount of Lorentz violation for different particle species. We focus on constraints from three high energy processes involving photons and electrons: photon de...

We study the question of whether a composite structure of elementary particles, with a length scale 1/Λ, can leave observable effects of non-locality and causality violation at higher energies (but . Λ). We formulate a model-independent approach based on BogoliubovShirkov formulation of causality. We analyze the relation between the fundamental theory (of finer constituents) and the derived the...

We re-evaluate the event rate expected in km-scale detectors for neutrinos from the direction of the Galactic Center (GC) in light of recent spectral measurements obtained by the HESS instrument for ∼TeV γ-radiation from this direction. In the most plausible scenario the re-evaluated event rate is smaller than that previously calculated—and here re-calculated—on the basis of EGRET data. However...

A system H with a Hagedorn-like mass spectrum imparts its unique temperature TH to any other system coupled to it. An H system radiates particles in preexisting physical and chemical equilibrium. These particles form a saturated vapor at temperature TH . This coexistence describes a first order phase transition. An H system is nearly indifferent to fragmentation into smaller H systems. A lower ...

THE URGE TO REDUCE THE FORMS of matter to a few elementary constituents must be very ancient. By 450 BCE, Empedocles had already developed or inherited a “standard model” in which everything was composed of four elements—Air, Earth, Fire, and Water. Thinking about the materials available to him, this is not a bad list. But as a predictive model of Nature, it has some obvious shortcomings. Succe...

We re-evaluate the event rate expected in km-scale detectors for neutrinos from the direction of the Galactic Center (GC) in light of recent results obtained by the HESS instrument for ∼TeV γ-radiation from this direction. Though (in the most plausible scenario) the re-evaluated event rate is smaller than that previously calculated—and here re-calculated—on the basis of EGRET data, the HESS GC ...

We discuss a numerical relation between the cosmological constant Λ [1] and the vacuum energy arising from the Casimir effect [2]. Many recent theories of the elementary particles invoke the existence of extra dimensions, beyond the familiar 4-dimensional space-time manifold. Often these extra dimensions are compact and have a finite range. In a particular model [3] the range R is of the order ...