We study the mixing of different kind of fields (scalar in 0+1D, scalar in 3+1D, fermion in 3+1D)... more We study the mixing of different kind of fields (scalar in 0+1D, scalar in 3+1D, fermion in 3+1D) treating the mixing term as an interaction. To this aim, we employ the usual perturbative series in the interaction picture. We find that expression for flavor changing probability exhibits corrections with respect to the usual quantum mechanical (e.g. neutrino) oscillation formula, in agreement with the result previously obtained in the non-perturbative flavor Fock space approach.
We consider two necessary and sufficient conditions for macrorealism recently appeared in the lit... more We consider two necessary and sufficient conditions for macrorealism recently appeared in the literature, known as no-signaling-in-time and arrow-of-time conditions, respectively, and study them in the context of neutrino flavor transitions, within both the plane wave description and the wave packet approach. We then compare the outcome of the above investigation with the implication of various formulations of Leggett–Garg inequalities. In particular, we show that the fulfillment of the addressed conditions for macrorealism in neutrino oscillations implies the fulfillment of the Leggett–Garg inequalities, whereas the converse is not true. Finally, in the framework of wave packet approach, we also prove that, for distances longer than the coherence length, the no-signaling-in-time condition is always violated whilst the Leggett–Garg inequalities are not.
The solutions of the Dirac equation are given in terms of bispinors, four-component objects which... more The solutions of the Dirac equation are given in terms of bispinors, four-component objects which include both spin and chirality as internal degrees of freedom. For massive particles, the Dirac equation couples components of the bispinor with different chiralities, yielding chiral oscillations. This phenomenon can be particularly relevant for recent proposals aimed at measuring non-relativistic cosmic neutrinos, and can find analogies in Dirac-like systems, such as graphene. In this paper, a concise review of chiral oscillations is presented, including their description with the Dirac's equation dynamics and the underlying group structure. Two paradigmatic cases of chiral oscillations in physical systems are shown: the effects on lepton-antineutrino spin quantum correlations, and neutrino flavor oscillations. Finally, extensions of recent theoretical investigations as well as future research developments are discussed.
The quantization of mixed (neutrino) fields in an accelerated background reveals a non-thermal na... more The quantization of mixed (neutrino) fields in an accelerated background reveals a non-thermal nature for Unruh radiation, which can be fitted by a Tsallis-like distribution function. However, for relativistic flavor neutrinos, which are represented by the standard Pontecorvo states, such a correction turns out to be negligible and thermality is restored. We show that the usage of Pontecorvo states for the calculation of the decay rate of an accelerated proton in the laboratory and comoving frames leads to consistent results and correctly implements the KMS thermal condition. Thus, the employment of these states in the above framework is not at odds with the principle of general covariance, in contrast to recent claims in the literature.
The evolution of single particle excitations of bilayer graphene under effects of non-Markovian n... more The evolution of single particle excitations of bilayer graphene under effects of non-Markovian noise is described with focus on the decoherence process of lattice-layer (LL) maximally entangled states. Once that the noiseless dynamics of an arbitrary initial state is identified by the correspondence between the tight-binding Hamiltonian for the AB-stacked bilayer graphene and the Dirac equation -- which includes pseudovector- and tensor-like field interactions -- the noisy environment is described as random fluctuations on bias voltage and mass terms. The inclusion of noisy dynamics reproduces the Ornstein-Uhlenbeck processes: a non-Markovian noise model with a well-defined Markovian limit. Considering that an initial amount of entanglement shall be dissipated by the noise, two profiles of dissipation are identified. On one hand, for eigenstates of the noiseless Hamiltonian, deaths and revivals of entanglement are identified along the oscillation pattern for long interaction period...
We show that the quantum linear harmonic oscillator can be obtained in the large N limit of a cla... more We show that the quantum linear harmonic oscillator can be obtained in the large N limit of a classical deterministic system with SU(1, 1) dynamical symmetry. This is done in analogy with recent work by G. ’t Hooft who investigated a deterministic system based on SU(2).
Flavor mixing of quantum fields was found to be responsible for the breakdown of the thermality o... more Flavor mixing of quantum fields was found to be responsible for the breakdown of the thermality of Unruh effect. Recently, this result was revisited in the context of nonextensive Tsallis thermostatistics, showing that the emergent vacuum condensate can still be featured as a thermal-like bath, provided that the underlying statistics is assumed to obey Tsallis prescription. This was analyzed explicitly for bosons. Here we extend this study to Dirac fermions and in particular to neutrinos. Working in the relativistic approximation, we provide an effective description of the modified Unruh spectrum in terms of the q-generalized Tsallis statistics, the q-entropic index being dependent on the mixing parameters $$\sin \theta $$ sin θ and $$\Delta m$$ Δ m . As opposed to bosons, we find $$q>1$$ q > 1 , which is indicative of the subadditivity regime of Tsallis entropy. An intuitive understanding of this result is discussed in relation to the nontrivial entangled structure exhibited ...
We review some aspects of the quantization of the damped harmonic oscillator. We derive the exact... more We review some aspects of the quantization of the damped harmonic oscillator. We derive the exact action for a damped mechanical system in the frame of the path integral formulation of the quantum Brownian motion problem developed by Schwinger and by Feynman and Vernon. The doubling of the phase-space degrees of freedom for dissipative systems and thermal field theories is discussed and the doubled variables are related to quantum noise effects. The ’t Hooft proposal, according to which the loss of information due to dissipation in a classical deterministic system manifests itself in the quantum features of the system, is analyzed and the quantum spectrum of the harmonic oscillator is shown to be originated from the dissipative character of the original classical deterministic system.
We consider a generalized uncertainty principle (GUP) corresponding to a deformation of the funda... more We consider a generalized uncertainty principle (GUP) corresponding to a deformation of the fundamental commutator obtained by adding a term quadratic in the momentum. From this GUP, we compute corrections to the Unruh effect and related Unruh temperature, by first following a heuristic derivation, and then a more standard field theoretic calculation. In the limit of small deformations, we recover the thermal character of the Unruh radiation. Corrections to the temperature at first order in the deforming parameter are compared for the two approaches, and found to be in agreement as for the dependence on the cubic power of the acceleration of the reference frame. The dependence of the shifted temperature on the frequency is also pointed out and discussed.
We comment on the recent paper by A. Tureanu (Eur. Phys. J. C 80: 68 (2020).). We show that defin... more We comment on the recent paper by A. Tureanu (Eur. Phys. J. C 80: 68 (2020).). We show that definition of oscillating neutrino states proposed in that work can be derived in a particular case of the Blasone-Vitiello approach, when mass vacuum is chosen as the physical vacuum. We discuss some problems of such an approach, which appears to be mathematically inconsistent and physically not acceptable.
We analyze the effects of gravity on neutrino wave packet decoherence. As a specific example, we ... more We analyze the effects of gravity on neutrino wave packet decoherence. As a specific example, we consider the gravitational field of a spinning spherical body described by the Lense–Thirring metric. By working in the weak-field limit and employing Gaussian wave packets, we show that the characteristic coherence length of neutrino oscillation processes is nontrivially affected, with the corrections being dependent on the mass and angular velocity of the gravity source. Possible experimental implications are finally discussed.
In a recent paper [Eur. Phys. J. C 80, 68 (2020)], a definition of oscillating neutrino states in... more In a recent paper [Eur. Phys. J. C 80, 68 (2020)], a definition of oscillating neutrino states in quantum field theory was proposed. We show that such definition can be derived as a particular case of the Blasone–Vitiello approach, when mass vacuum is chosen as the physical vacuum. We discuss some problems of such an approach, which appears to be mathematically inconsistent and physically not acceptable.
International Journal of Geometric Methods in Modern Physics, 2020
The study of the damped harmonic oscillator shows that dissipation could be seen at the origin of... more The study of the damped harmonic oscillator shows that dissipation could be seen at the origin of the zero point energy, which is the signature of quantum behavior. This is in accord with ’t Hooft proposal that loss of information in a completely deterministic dynamics would play a rôle in the quantum mechanical nature of our world. We show the equivalence, within quite general conditions, between the pair of a damped oscillator and its time-reversed image and electrodynamics. The ground state of the damped-amplified oscillator pair appears to be a finite temperature coherent two-mode squeezed state with fractal self-similarity properties and the modes are maximally entangled. Temperature is strictly related to the zero point energy.
We study the mixing of different kind of fields (scalar in 0+1D, scalar in 3+1D, fermion in 3+1D)... more We study the mixing of different kind of fields (scalar in 0+1D, scalar in 3+1D, fermion in 3+1D) treating the mixing term as an interaction. To this aim, we employ the usual perturbative series in the interaction picture. We find that expression for flavor changing probability exhibits corrections with respect to the usual quantum mechanical (e.g. neutrino) oscillation formula, in agreement with the result previously obtained in the non-perturbative flavor Fock space approach.
We consider two necessary and sufficient conditions for macrorealism recently appeared in the lit... more We consider two necessary and sufficient conditions for macrorealism recently appeared in the literature, known as no-signaling-in-time and arrow-of-time conditions, respectively, and study them in the context of neutrino flavor transitions, within both the plane wave description and the wave packet approach. We then compare the outcome of the above investigation with the implication of various formulations of Leggett–Garg inequalities. In particular, we show that the fulfillment of the addressed conditions for macrorealism in neutrino oscillations implies the fulfillment of the Leggett–Garg inequalities, whereas the converse is not true. Finally, in the framework of wave packet approach, we also prove that, for distances longer than the coherence length, the no-signaling-in-time condition is always violated whilst the Leggett–Garg inequalities are not.
The solutions of the Dirac equation are given in terms of bispinors, four-component objects which... more The solutions of the Dirac equation are given in terms of bispinors, four-component objects which include both spin and chirality as internal degrees of freedom. For massive particles, the Dirac equation couples components of the bispinor with different chiralities, yielding chiral oscillations. This phenomenon can be particularly relevant for recent proposals aimed at measuring non-relativistic cosmic neutrinos, and can find analogies in Dirac-like systems, such as graphene. In this paper, a concise review of chiral oscillations is presented, including their description with the Dirac's equation dynamics and the underlying group structure. Two paradigmatic cases of chiral oscillations in physical systems are shown: the effects on lepton-antineutrino spin quantum correlations, and neutrino flavor oscillations. Finally, extensions of recent theoretical investigations as well as future research developments are discussed.
The quantization of mixed (neutrino) fields in an accelerated background reveals a non-thermal na... more The quantization of mixed (neutrino) fields in an accelerated background reveals a non-thermal nature for Unruh radiation, which can be fitted by a Tsallis-like distribution function. However, for relativistic flavor neutrinos, which are represented by the standard Pontecorvo states, such a correction turns out to be negligible and thermality is restored. We show that the usage of Pontecorvo states for the calculation of the decay rate of an accelerated proton in the laboratory and comoving frames leads to consistent results and correctly implements the KMS thermal condition. Thus, the employment of these states in the above framework is not at odds with the principle of general covariance, in contrast to recent claims in the literature.
The evolution of single particle excitations of bilayer graphene under effects of non-Markovian n... more The evolution of single particle excitations of bilayer graphene under effects of non-Markovian noise is described with focus on the decoherence process of lattice-layer (LL) maximally entangled states. Once that the noiseless dynamics of an arbitrary initial state is identified by the correspondence between the tight-binding Hamiltonian for the AB-stacked bilayer graphene and the Dirac equation -- which includes pseudovector- and tensor-like field interactions -- the noisy environment is described as random fluctuations on bias voltage and mass terms. The inclusion of noisy dynamics reproduces the Ornstein-Uhlenbeck processes: a non-Markovian noise model with a well-defined Markovian limit. Considering that an initial amount of entanglement shall be dissipated by the noise, two profiles of dissipation are identified. On one hand, for eigenstates of the noiseless Hamiltonian, deaths and revivals of entanglement are identified along the oscillation pattern for long interaction period...
We show that the quantum linear harmonic oscillator can be obtained in the large N limit of a cla... more We show that the quantum linear harmonic oscillator can be obtained in the large N limit of a classical deterministic system with SU(1, 1) dynamical symmetry. This is done in analogy with recent work by G. ’t Hooft who investigated a deterministic system based on SU(2).
Flavor mixing of quantum fields was found to be responsible for the breakdown of the thermality o... more Flavor mixing of quantum fields was found to be responsible for the breakdown of the thermality of Unruh effect. Recently, this result was revisited in the context of nonextensive Tsallis thermostatistics, showing that the emergent vacuum condensate can still be featured as a thermal-like bath, provided that the underlying statistics is assumed to obey Tsallis prescription. This was analyzed explicitly for bosons. Here we extend this study to Dirac fermions and in particular to neutrinos. Working in the relativistic approximation, we provide an effective description of the modified Unruh spectrum in terms of the q-generalized Tsallis statistics, the q-entropic index being dependent on the mixing parameters $$\sin \theta $$ sin θ and $$\Delta m$$ Δ m . As opposed to bosons, we find $$q>1$$ q > 1 , which is indicative of the subadditivity regime of Tsallis entropy. An intuitive understanding of this result is discussed in relation to the nontrivial entangled structure exhibited ...
We review some aspects of the quantization of the damped harmonic oscillator. We derive the exact... more We review some aspects of the quantization of the damped harmonic oscillator. We derive the exact action for a damped mechanical system in the frame of the path integral formulation of the quantum Brownian motion problem developed by Schwinger and by Feynman and Vernon. The doubling of the phase-space degrees of freedom for dissipative systems and thermal field theories is discussed and the doubled variables are related to quantum noise effects. The ’t Hooft proposal, according to which the loss of information due to dissipation in a classical deterministic system manifests itself in the quantum features of the system, is analyzed and the quantum spectrum of the harmonic oscillator is shown to be originated from the dissipative character of the original classical deterministic system.
We consider a generalized uncertainty principle (GUP) corresponding to a deformation of the funda... more We consider a generalized uncertainty principle (GUP) corresponding to a deformation of the fundamental commutator obtained by adding a term quadratic in the momentum. From this GUP, we compute corrections to the Unruh effect and related Unruh temperature, by first following a heuristic derivation, and then a more standard field theoretic calculation. In the limit of small deformations, we recover the thermal character of the Unruh radiation. Corrections to the temperature at first order in the deforming parameter are compared for the two approaches, and found to be in agreement as for the dependence on the cubic power of the acceleration of the reference frame. The dependence of the shifted temperature on the frequency is also pointed out and discussed.
We comment on the recent paper by A. Tureanu (Eur. Phys. J. C 80: 68 (2020).). We show that defin... more We comment on the recent paper by A. Tureanu (Eur. Phys. J. C 80: 68 (2020).). We show that definition of oscillating neutrino states proposed in that work can be derived in a particular case of the Blasone-Vitiello approach, when mass vacuum is chosen as the physical vacuum. We discuss some problems of such an approach, which appears to be mathematically inconsistent and physically not acceptable.
We analyze the effects of gravity on neutrino wave packet decoherence. As a specific example, we ... more We analyze the effects of gravity on neutrino wave packet decoherence. As a specific example, we consider the gravitational field of a spinning spherical body described by the Lense–Thirring metric. By working in the weak-field limit and employing Gaussian wave packets, we show that the characteristic coherence length of neutrino oscillation processes is nontrivially affected, with the corrections being dependent on the mass and angular velocity of the gravity source. Possible experimental implications are finally discussed.
In a recent paper [Eur. Phys. J. C 80, 68 (2020)], a definition of oscillating neutrino states in... more In a recent paper [Eur. Phys. J. C 80, 68 (2020)], a definition of oscillating neutrino states in quantum field theory was proposed. We show that such definition can be derived as a particular case of the Blasone–Vitiello approach, when mass vacuum is chosen as the physical vacuum. We discuss some problems of such an approach, which appears to be mathematically inconsistent and physically not acceptable.
International Journal of Geometric Methods in Modern Physics, 2020
The study of the damped harmonic oscillator shows that dissipation could be seen at the origin of... more The study of the damped harmonic oscillator shows that dissipation could be seen at the origin of the zero point energy, which is the signature of quantum behavior. This is in accord with ’t Hooft proposal that loss of information in a completely deterministic dynamics would play a rôle in the quantum mechanical nature of our world. We show the equivalence, within quite general conditions, between the pair of a damped oscillator and its time-reversed image and electrodynamics. The ground state of the damped-amplified oscillator pair appears to be a finite temperature coherent two-mode squeezed state with fractal self-similarity properties and the modes are maximally entangled. Temperature is strictly related to the zero point energy.
Uploads
Papers by Massimo Blasone