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Giuseppe Vitiello

Publications and source records attributed to Giuseppe Vitiello.

At least 55 records · Page 3Linked to original sources
arXiv2008

Dissipation and spontaneous symmetry breaking in brain dynamics

We compare the predictions of the dissipative quantum model of brain with neurophysiological data collected from electroencephalograms resulting from high-density arrays fixed on the surfaces of primary sensory and limbic areas of trained rabbits and cats. Functional brain imaging in relation to behavior reveals the formation of coherent domains of synchronized neuronal oscillatory activity and phase transitions predicted by the dissipative model.

q-bio.NC↗
arXiv2006

Links. Relating different physical systems through the common QFT algebraic structure

In this report I review some aspects of the algebraic structure of QFT related with the doubling of the degrees of freedom of the system under study. I show how such a doubling is related to the characterizing feature of QFT consisting in the existence of infinitely many unitarily inequivalent representations of the canonical (anti-)commutation relations and how this is described by the q-deformed Hopf algebra. I consider several examples, such as the damped harmonic oscillator, the quantum Brownian motion, thermal field theories, squeezed states, classical-to-quantum relation, and show the analogies, or links, among them arising from the common algebraic structure of the q-deformed Hopf algebra.

hep-th↗
arXiv2006

The role of the electromagnetic field in the formation of domains in the process of symmetry breaking phase transitions

In the framework of quantum field theory we discuss the emergence of a phase locking among the electromagnetic modes and the matter components on an extended space-time region. We discuss the formation of extended domains exhibiting in their fundamental states non-vanishing order parameters, whose existence is not included in the Lagrangian. Our discussion is motivated by the interest in the study of the general problem of the stability of mesoscopic and macroscopic complex systems arising from fluctuating quantum components in connection with the problem of defect formation during the process of non-equilibrium symmetry breaking phase transitions characterized by an order parameter.

cond-mat.other↗
arXiv2005

Nonlinear brain dynamics as macroscopic manifestation of underlying many-body field dynamics

Neural activity patterns related to behavior occur at many scales in time and space from the atomic and molecular to the whole brain. Here we explore the feasibility of interpreting neurophysiological data in the context of many-body physics by using tools that physicists have devised to analyze comparable hierarchies in other fields of science. We focus on a mesoscopic level that offers a multi-step pathway between the microscopic functions of neurons and the macroscopic functions of brain systems revealed by hemodynamic imaging. We use electroencephalographic (EEG) records collected from high-density electrode arrays fixed on the epidural surfaces of primary sensory and limbic areas in rabbits and cats trained to discriminate conditioned stimuli (CS) in the various modalities. High temporal resolution of EEG signals with the Hilbert transform gives evidence for diverse intermittent spatial patterns of amplitude (AM) and phase modulations (PM) of carrier waves that repeatedly re-synchronize in the beta and gamma ranges at near zero time lags over long distances. The dominant mechanism for neural interactions by axodendritic synaptic transmission should impose distance-dependent delays on the EEG oscillations owing to finite propagation velocities. It does not. EEGs instead show evidence for anomalous dispersion: the existence in neural populations of a low velocity range of information and energy transfers, and a high velocity range of the spread of phase transitions. This distinction labels the phenomenon but does not explain it. In this report we explore the analysis of these phenomena using concepts of energy dissipation, the maintenance by cortex of multiple ground states corresponding to AM patterns, and the exclusive selection by spontaneous breakdown of symmetry (SBS) of single states in sequences.

q-bio.OT↗
arXiv2005

Lepton charge and neutrino mixing in pion decay processes

We consider neutrino mixing and oscillations in quantum field theory and compute the neutrino lepton charge in decay processes where neutrinos are generated. We also discuss the proper definition of flavor charge and states and clarify the issues of the possibility of different mass parameters in field mixing.

hep-ph↗
arXiv2005

Nonlinear brain dynamics and many-body field dynamics

We report measurements of the brain activity of subjects engaged in behavioral exchanges with their environments. We observe brain states which are characterized by coordinated oscillation of populations of neurons that are changing rapidly with the evolution of the meaningful relationship between the subject and its environment, established and maintained by active perception. Sequential spatial patterns of neural activity with high information content found in sensory cortices of trained animals between onsets of conditioned stimuli and conditioned responses resemble cinematographic frames. They are not readily amenable to description either with classical integrodifferential equations or with the matrix algebras of neural networks. Their modeling is provided by field theory from condensed matter physics.

q-bio.NC↗
arXiv2005

Cooling many particles at once

We propose a mechanism for the collective cooling of a large number N of trapped particles to very low temperatures by applying red-detuned laser fields and coupling them to the quantized field inside an optical resonator. The dynamics is described by what appears to be rate equations, but where some of the major quantities are coherences and not populations. The cooperative behavior of the system provides cooling rates of the same order of magnitude as the cavity decay rate kappa. This constitutes a significant speed-up compared to other cooling mechanisms since kappa can, in principle, be as large as square root of N times the single-particle cavity or laser coupling constant.

quant-ph↗
arXiv2004

Cooling many particles to very low temperatures

In a recent paper [Beige, Knight, and Vitiello, quant-ph/0404160], we showed that a large number N of particles can be cooled very efficiently using a bichromatic interaction. The particles should be excited by red-detuned laser fields while coupling to the quantized field mode inside a resonant and leaky optical cavity. When the coupling constants are for all particles the same, a collective behavior can be generated and the cooling rate can be as large as square root of N times the single-particle coupling constants. Here we study the algebraic structure of the dynamics and the origin of the collective cooling process in more detail.

quant-ph↗
arXiv2004

Neutrino mixing as a source for cosmological constant

We report on recent results showing that neutrino mixing may lead to a non-zero contribution to the cosmological constant. This contribution is of a completely different nature with respect to the usual one by a massive spinor field. We also study the problem of field mixing in Quantum Field Theory in curved space-time, for the case of a scalar field in the Friedmann-Robertson-Walker metric.

hep-th↗
arXiv2004

Neutrino mixing and cosmological constant

We report on the recent result that the non--perturbative vacuum structure associated with neutrino mixing leads to a non--zero contribution to the value of the cosmological constant. Its value is estimated by using the natural cut--off appearing in the quantum field theory formalism for neutrino mixing.

hep-th↗
arXiv2004

The dissipative brain

I review the dissipative quantum model of brain and discuss its recent developments related with the role of entanglement, quantum noise and chaos. Some comments on consciousness in the frame of the dissipative model are also presented. Dissipation seems to account for the medial character of consciousness, for its being in the present (the Now), its un-dividable unity, its intrinsic subjectivity (autonomy). Finally, essential features of a conscious artificial device, if ever one can construct it, are briefly commented upon, also in relation to a device able to exhibit mistakes in its behavior. The name I give to such a hypothetical device is Spartacus.

q-bio.OT↗
arXiv2004

Phenomenology of flavor oscillations with non-perturbative effects from quantum field theory

We analyze phenomenological aspects of the quantum field theoretical formulation of meson mixing and obtain the exact oscillation formula in the presence of the decay. This formula is different from quantum mechanical formula by additional high-frequency oscillation terms. In the infinite volume limit, the space of the flavor quantum states is unitarily inequivalent to the space of energy eigenstates.

hep-ph↗
arXiv2004

Quantum noise induced entanglement and chaos in the dissipative quantum model of brain

We discuss some features of the dissipative quantum model of brain in the frame of the formalism of quantum dissipation. Such a formalism is based on the doubling of the system degrees of freedom. We show that the doubled modes account for the quantum noise in the fluctuating random force in the system-environment coupling. Remarkably, such a noise manifests itself through the coherent structure of the system ground state. The entanglement of the system modes with the doubled modes is shown to be permanent in the infinite volume limit. In such a limit the trajectories in the memory space are classical chaotic trajectories.

quant-ph↗
arXiv2003

Classical chaotic trajectories in quantum field theory

Trajectories in the space of the unitarily inequivalent representations of the canonical commutation relations are shown to be classical trajectories. Under convenient conditions, they may exhibit properties typical of chaotic behavior in classical nonlinear dynamics. Quantum noise in fluctuating random force in the system--environment coupling and system--environment entanglement is also discussed.

hep-th↗
arXiv2003

Quantum Field Theory of particle mixing and oscillations

We report on recent results on the Quantum Field Theory of mixed particles. The quantization procedure is discussed in detail, both for fermions and for bosons and the unitary inequivalence of the flavor and mass representations is proved. Oscillation formulas exhibiting corrections with respect to the usual quantum mechanical ones are then derived.

hep-ph↗
arXiv2002

Time-reversal violation as loop-antiloop symmetry breaking: the Bessel equation, group contraction and dissipation

We show that the Bessel equation can be cast, by means of suitable transformations, into a system of two damped/amplified parametric oscillator equations. The relation with the group contraction mechanism is analyzed and the breakdown of loop-antiloop symmetry due to group contraction manifests itself as violation of time-reversal symmetry. A preliminary discussion of the relation between some infinite dimensional loop-algebras, such as the Virasoro-like algebra, and the Euclidean algebras e(2) and e(3) is also presented.

hep-th↗