1,721,027 research outputs found
q-generalized Tsallis thermostatistics in Unruh effect for mixed fields
Full text linkIt was shown that the particle distribution detected by a uniformly accelerated observer in the inertial vacuum (Unruh effect) deviates from the pure Planckian spectrum when considering the superposition of fields with different masses. Here, we elaborate on the statistical origin of this phenomenon. In a suitable regime, we provide an effective description of the emergent distribution in terms of the nonextensive q-generalized statistics based on Tsallis entropy. This picture allows us to establish a nontrivial relation between the q-entropic index and the characteristic mixing parameters sinθ and Δm. In particular, we infer that q<1, indicating the superadditive feature of Tsallis entropy in this framework. We discuss our result in connection with the entangled condensate structure acquired by the quantum vacuum for mixed fields
Lorentz boosts of bispinor Bell-like states
No full textWe describe in this paper the effects of Lorentz boost on the quantum entanglement encoded in two-particle Dirac bispinor Bell-like states. Each particle composing the system described in this formalism has three degrees of freedom: spin, chirality, and momentum, and the joint state can be interpreted as a 6 qubit state. Given the transformation law of bispinor under boosts, we compute the change of the Meyer-Wallach global measure of quantum entanglement due to the frame transformation and study its equivalence to the results obtained for the relativistic spin 1/2 Bell-like states, constructed in the framework of the irreducible representations of the Lorentz group. We verify that the monotonic increase of the global entanglement under boosts for ultra-relativistic states is solely due to an increasing of the entanglement associated with the spins subsystems. For such ultra-relativistic states, the entanglement related to the chirality degrees of freedom is invariant, and the variation of the global entanglement of bispinor states is the same as the one calculated for relativistic spin 1/2 states. We also show that the particle-particle entanglement is invariant under boosts for any Bell-like state
Unified formalism for Thermal Quantum Field Theories: A geometric viewpoint
No full textIn this paper we study a unified formalism for Thermal Quantum Field Theories, i.e., for the Matsubara approach, Thermo Field Dynamics and the Path Ordered Method. To do so, we employ a mechanism akin to the Hawking effect which explores a relationship between the concept of temperature and spacetimes endowed with event-horizons. In particular, we consider an eight dimensional static spacetime, the so-called– spacetime, which we show to form an appropriate geometric background for generic Thermal Quantum Field Theories. Within this framework, the different formalisms of Thermal Field Theory are unified in a very natural way via various analytical continuations and the set of time-paths used in the Path Ordered Method is interpreted in geometric terms. We also explain reported inconsistencies inherent in the Thermo Field Dynamics through the appearance of horizons (and ensuing loss of information) in the eta–\xi spacetime
Dynamical generation of flavor vacuum and Lorentz invariance
No full textIn this paper we review dynamical generation of field mixing after chiral symmetry breaking. We also study the explicit form of Lorentz boosts transformations of flavor states in a two-flavor scalar model with field mixing. We find that Lorentz symmetry is spontaneously broken on flavor vacuum because of its dynamically generated condensate structure
Chiral symmetry-breaking schemes and dynamical generation of masses and field mixing
No full textIn this paper we review dynamical generation of field mixing after chiral symmetry breaking. We also study the explicit form of discrete transformations of flavor states in a two-flavor scalar model with field mixing. We find that CPT symmetry is spontaneously broken on flavor vacuum because of its dynamically generated condensate structure
Single particle entanglement of a massive relativistic particle: Dirac bispinors and spin 1/2 states
No full textIn this paper we study the single particle entanglement induced by a Lorentz boost. We described the particle as a solution of the free Dirac equation, a Dirac bispinor, and compare the induced momentum-spin entanglement with the result obtained in the widely considered framework of relativistic spin 1/2 states. The spin linear entropy for both approaches agree in the ultra relativistic limit. We also verify that the spin-momentum entanglement differers from the spin entropy for the bispinorial case, indicating a true multipartite entanglement involving the degrees of freedom of a Dirac bispinor state: momentum, spin and intrinsic parity. The fact that Dirac bispinors belongs to an irreducible representation of the complete Lorentz group, which also included parity as a symmetry, is the ultimate reason behind such non-trivial structure
Flavor neutrinos as unstable particles
No full textIn this paper we review flavor-energy uncertainty relations for neutrino oscillations in quantum field theory, putting in evidence the analogy with the case of unstable particles. Our study reveals that flavor neutrinos are intrinsically characterized by an energy distribution with a non-vanishing width. In the ultrarelativistic limit, the energy width is bounded from below by the inverse of the oscillation length, which plays the same role as the half-life for unstable particles
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