Cosmological effects of neutrino mixing
We report on the recent result that a contribution to the dark energy can be achieved by the vacuum condensate induced by neutrino mixing phenomenon.
hep-th↗
arXiv subjects
M. Blasone
Publications and source records attributed to M. Blasone.
Quantum Behavior of Deterministic Systems with Information Loss. Path Integral Approach
't Hooft's derivation of quantum from classical physics is analyzed by means of the classical path integral of Gozzi et al.. It is shown how the key element of this procedure - the loss of information constraint - can be implemented by means of Faddeev-Jackiw's treatment of constrained systems. It is argued that the emergent quantum systems are identical with systems obtained in [Phys.Rev. A 71 (2005) 052507] through Dirac-Bergmann's analysis. We illustrate our approach with two simple examples - free particle and linear harmonic oscillator. Potential Liouville anomalies are shown to be absent.
quant-ph↗
Lorentz invariance for mixed neutrinos
We show that a proper field theoretical treatment of mixed (Dirac) neutrinos leads to non-trivial dispersion relations for the flavor states. We analyze such a situation in the framework of the non-linear relativity schemes recently proposed by Magueijo and Smolin. We finally examine the experimental implications of our theoretical proposals by considering the spectrum and the end-point of beta decay in tritium.
hep-ph↗
Quantum fields with topological defects
Domain walls, strings and monopoles are extended objects, or defects, of quantum origin with topologically non--trivial properties and macroscopic behavior. They are described in Quantum Field Theory in terms of inhomogeneous condensates. We review the related formalism in the framework of the spontaneous breakdown of symmetry.
math-ph↗
Neutrino mixing contribution to the cosmological constant
We show that the non-perturbative vacuum structure associated with neutrino mixing leads to a non-zero contribution to the value of the cosmological constant. Such a contribution comes from the specific nature of the mixing phenomenon. Its origin is completely different from the one of the ordinary contribution of a massive spinor field. We estimate this neutrino mixing contribution by using the natural cut--off appearing in the quantum field theory formalism for neutrino mixing and oscillation.
gr-qc↗
Group theoretical aspects of neutrino mixing in Quantum Field Theory
By resorting to recent results on the Quantum Field Theory of mixed particles, we discuss some aspects of three flavor neutrino mixing. Particular emphasis is given to the related algebraic structures and their deformation in the presence of CP violation. A novel geometric phase related to CP violation is introduced.
hep-ph↗
Observables in the Quantum Field Theory of neutrino mixing and oscillations
We report about recent results on the Quantum Field Theory of neutrino mixing and oscillations. A discussion of the relevant observables for flavor fields is given, leading to oscillation formulas which exhibit corrections with respect to the usual ones.
hep-ph↗
Quantum limit of deterministic theories
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). Among the advantages of our model based on a non--compact group is the fact that the ground state energy is uniquely fixed by the choice of the representation.
quant-ph↗
Dissipation, Emergent Quantization and Quantum Fluctuations
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.
quant-ph↗
Quantization, group contraction and zero point energy
We study algebraic structures underlying 't Hooft's construction relating classical systems with the quantum harmonic oscillator. The role of group contraction is discussed. We propose the use of SU(1,1) for two reasons: because of the isomorphism between its representation Hilbert space and that of the harmonic oscillator and because zero point energy is implied by the representation structure. Finally, we also comment on the relation between dissipation and quantization.
quant-ph↗
Understanding flavor mixing in Quantum Field Theory
We report on recent results showing that a rich non-perturbative vacuum structure is associated with flavor mixing in Quantum Field Theory. We treat explicitly the case of mixing among three generations of Dirac fermions. Exact oscillation formulas are presented exhibiting new features with respect to the usual ones. CP and T violation are also discussed.
hep-th↗
On Normal ordering and Canonical transformations in Thermal Field Theory
We look at a real scalar field in thermal equilibrium in the context of the new normal ordering and field split defined by Evans and Steer. We show that the field split defines a natural canonical transformation, but that this transformation differs from others known in thermal field theory.
hep-ph↗
Phase Coherence in Quantum Brownian Motion
The quantum theory of Brownian motion is discussed in the Schwinger version wherein the notion of a coordinate moving forward in time $x(t)$ is replaced by two coordinates, $x_+(t)$ moving forward in time and $x_-(t)$ moving backward in time. The role of the doubling of the degrees of freedom is illustrated for the case of electron beam two slit diffraction experiments. Interference is computed with and without dissipation (described by a thermal bath). The notion of a dissipative interference phase, closely analogous to the Aharonov-Bohm magnetic field induced phase, is explored.
quant-ph↗
Thermalization of a Quark-Gluon Plasma
The thermalization time for a Quark-Gluon-Plasma is estimated from a quantum transport model beyond the quasi-particle approach (or kinetic gas theory). While our ansatz is crude concerning the properties of ''real'' quarks and gluons, it nevertheless takes very serious the basic principles of quantum field theory for non-equilibrium states. It is found, that the thermalization time obtained from quantum transport theory is substantially longer than from kinetic theory. In our view this casts some doubts on scenarios which a priori assume a thermalized quark gluon plasma.
hep-ph↗
Mixing Transformations in Quantum Field Theory and Neutrino Oscillations
Field mixing transformations are studied in quantum field theory and the generator of the transformations is found to induce an SU(2) coherent structure in the vacuum state, both for bosons and for fermions. The Fock space for mixed fields is unitarily inequivalent to the Fock space of the unmixed fields in the infinite volume limit. We study neutrino mixing and oscillations and find that the oscillation amplitude is depressed by a factor which is momentum and mass dependent. The usual formula is recovered in the relativistic limit. Phenomenological features of the modified oscillation formula are discussed. Finally, preliminary results of the Green's function formalism are presented.
hep-ph↗
Dissipation and Topologically Massive Gauge Theories in Pseudoeuclidean Plane
In the pseudo-euclidean metrics Chern-Simons gauge theory in the infrared region is found to be associated with dissipative dynamics. In the infrared limit the Lagrangian of 2+1 dimensional pseudo-euclidean topologically massive electrodynamics has indeed the same form of the Lagrangian of the damped harmonic oscillator. On the hyperbolic plane a set of two damped harmonic oscillators, each other time-reversed, is shown to be equivalent to a single undamped harmonic oscillator. The equations for the damped oscillators are proven to be the same as the ones for the Lorentz force acting on two particles carrying opposite charge in a constant magnetic field and in the electric harmonic potential. This provides an immediate link with Chern-Simons-like dynamics of Bloch electrons in solids propagating along the lattice plane with hyperbolic energy surface. The symplectic structure of the reduced theory is finally discussed in the Dirac constrained canonical formalism.
hep-th↗
Neutrino Mixing and Oscillations in Quantum Field Theory
We show that the generator of field mixing transformations in Quantum Field Theory induces a non trivial structure in the vacuum which turns out to be a coherent state, both for bosons and for fermions, although with a different condensate structure. The Fock space for mixed fields is unitarily inequivalent to the Fock space of the massive (free) fields in the infinite volume limit. As a practical application we study neutrino mixing and oscillations. A new oscillation formula is found where the oscillation amplitude is depressed, with respect to the usual one, by a factor which is momentum and mass dependent. In the relativistic limit, the usual formula is recovered. We finally discuss in some detail phenomenological features of the modified oscillation formula.
hep-ph↗
Squeezed Neutrino Oscillations in Quantum Field Theory
By resorting to recent results on fermion mixing which show that the Fock space of definite flavor states is unitarily inequivalent to the Fock space of definite mass states, we discuss the phenomenological implications on the neutrino oscillation formula. For finite momentum the oscillation amplitude is depressed, or "squeezed", by a momentum dependent factor. In the relativistic limit the conventional oscillation formula is recovered.
hep-ph↗