Narrow Results

Little is known about the physics frontier of strong acceleration; both classical and quantum physics need further development in order to be able to address this newly accessible area of physics. In this lecture we discuss what strong acceleration means, possible experiments using electron-laser collisions, and data available from ultra-relativistic heavy ion collisions. We review the foundations of the current understanding of charged particle dynamics in presence of critical forces and discuss the radiation reaction inconsistency in electromagnetic theory and the apparent relation with quantum physics and strong field particle production phenomena. The role of the quantum vacuum as an inertial reference frame is emphasized, as well as the absence of such a 'Machian' reference frame in the conventional classical limit of quantum field theory.

The electron vacuum fluctuations measured by do not vanish in an externally applied electric field ℰ. For an exactly constant field, that is for vacuum fluctuations in presence of a constant accelerating force, we show that has a Boson-like structure with spectral state density tanh^-1(E/m) and temperature T_M = eℰ/mπ = a_v/π. Considering the vacuum fluctuations of 'classical' gyromagnetic ratio g = 1 particles we find Fermi-like structure with the same spectral state density at a smaller temperature T₁ = a_v/2π which corresponds to the Unruh temperature of an accelerated observer.

The first three years of the LHC experiments at CERN have ended with "the nightmare scenario": all tests, confirm the Standard Model of Particles so well that theorists must search for new physics without any experimental guidance. The supersymmetric theories, a privileged candidate for new physics, are nearly excluded. As a potential escape from the crisis, we propose thinking about a series of astonishing relations suggesting fundamental interconnections between the quantum world and the large scale Universe. It seems reasonable that, for instance, the equation relating a quark–antiquark pair with the fundamental physical constants and cosmological parameters must be a sign of new physics. One of the intriguing possibilities is interpreting our relations as a signature of the quantum vacuum containing the virtual gravitational dipoles.

The relativistic hydrodynamical equations are being examined with the aim of extracting the quantum-mechanical equations (the relativistic Klein–Gordon equation and the Schrödinger equation in the non-relativistic limit). In both cases we find the quantum potential, which follows from pressure gradients within a superfluid vacuum medium. This special fluid, endowed with viscosity allows to describe emergence of the flat orbital speeds of spiral galaxies. The viscosity averaged on time vanishes, but its variance is different from zero. It is a function fluctuating about zero. Therefore, the flattening is the result of the energy exchange of the torque with zero-point fluctuations of the physical vacuum on the ultra-low frequencies.

We want to study the influence of the quantum vacuum on light propagation. At first, by working in the standard linear quantum theory of the electromagnetic fields, it is shown that the electric permittivity and the magnetic permeability of the vacuum medium are changed; but, the resulting speed of light is not modified. Then, taking into account nonlinear effects by considering the Euler–Heisenberg Lagrangian, the corresponding zero point (vacuum) energy and the resulting modification of the speed of light are found up to the first nonvanishing correction.

We investigate Bose-Einstein condensation of a gas of non-interacting Bose particles moving in the background of a periodic lattice of delta functions. In the one-dimensional case, where one has no condensation in the free case, we showed that this property persist also in the presence of the lattice. In addition we formulated some conditions on the spectral functions which would allow for condensation.

In this paper, we will review, through various examples, some ideas connecting the physics of the quantum vacuum and the Casimir effect with the mechanism of symmetry breaking in different backgrounds. In the first example, we will discuss how the quantum vacuum energy is altered by the presence of nonlinearities in the underlying quantum field theory in a way that depends on the spatial dimensionality, as dictated by the Mermin–Wagner–Hohenberg–Coleman theorem. In the second example, we will explore how the combination of boundary effects and (discrete) chiral symmetry breaking can affect the thermodynamical behavior of a system of interacting fermions, and how this is reflected on the Casimir force. Even in the simplest setup of two parallel plates, two interesting things happen: first, the order of the transition through which discrete chiral symmetry may be broken/restored changes from second-order for infinitely large separation to first-order for a finite separation between the boundaries. Second, a peculiar behavior in the fermion condensate occurs, resulting in the appearance of two different phases (massless and massive) in the Casimir force. In the third example, we will also be concerned with the Casimir effect on an interacting fermion background over a string of finite length. Using a self-consistent method, we will show how a nontrivial behavior in the Casimir force arises, displaying a switch from an attractive to a repulsive regime, as a result of the competing effects due to the usual attractive Casimir force and a repulsive component coming from the condensate.

In this work, explicit expressions for the transition rates of an isotropic quantum charged harmonic oscillator in the vicinity of a perfectly conducting half-space under the influence of an external classical source are obtained. In the absence of external sources, it is shown that the decay rate of an initially exited state of the oscillator is a periodic function in terms of the normalized distance to the plate. The modified transition rates in the presence of external classical sources are obtained in the large-time limit indicating a contribution proportional to the squared module of the Fourier transform of the external source. In the absence of the conducting plate and external sources, the results are in agreement with the free space case. The problem is generalized to the case of a real conducting half-space.

The process of gravitationally-induced particle creation (Hawking radiation), if it exists, necessitates, in accordance with general thermodynamic principles, a corresponding process of gravitationally-induced particle resorption into the vacuum. Although the former process occurs in the external vicinity of the Schwarzschild surface where matter density is relatively low, the latter process would be expected to occur inside the Schwarzschild surface where the stellar material is enormously compressed and fermions fill all quantum states up to the Fermi level. I show that the occurrence of particle resorption provides a general mechanism, irrespective of the interactions of the constituent particles, which halts the collapse of a black hole to a singular point and leads to an equilibrium state of macroscopic extent.

The photon polarization tensor is the central building block of an effective theory description of photon propagation in the quantum vacuum. It accounts for the vacuum fluctuations of the underlying theory, and in the presence of external electromagnetic fields, gives rise to such striking phenomena as vacuum birefringence and dichroism. Standard approximations of the polarization tensor are often restricted to on-the-light-cone dynamics in homogeneous electromagnetic fields, and are limited to certain momentum regimes only. We devise two different strategies to go beyond these limitations: First, we aim at obtaining novel analytical insights into the photon polarization tensor for homogeneous fields, while retaining its full momentum dependence. Second, we employ wordline numerical methods to surpass the constant-field limit.

In this paper, we will review, through various examples, some ideas connecting the physics of the quantum vacuum and the Casimir effect with the mechanism of symmetry breaking in different backgrounds. In the first example, we will discuss how the quantum vacuum energy is altered by the presence of nonlinearities in the underlying quantum field theory in a way that depends on the spatial dimensionality, as dictated by the Mermin–Wagner–Hohenberg–Coleman theorem. In the second example, we will explore how the combination of boundary effects and (discrete) chiral symmetry breaking can affect the thermodynamical behavior of a system of interacting fermions, and how this is reflected on the Casimir force. Even in the simplest setup of two parallel plates, two interesting things happen: first, the order of the transition through which discrete chiral symmetry may be broken/restored changes from second-order for infinitely large separation to first-order for a finite separation between the boundaries. Second, a peculiar behavior in the fermion condensate occurs, resulting in the appearance of two different phases (massless and massive) in the Casimir force. In the third example, we will also be concerned with the Casimir effect on an interacting fermion background over a string of finite length. Using a self-consistent method, we will show how a nontrivial behavior in the Casimir force arises, displaying a switch from an attractive to a repulsive regime, as a result of the competing effects due to the usual attractive Casimir force and a repulsive component coming from the condensate.

The work-in-progress on the conjectured origin of the inertia reaction force (Newton's Second Law) in quantum vacuum fields is discussed and reviewed. It is first pointed out that the inertia reaction force is not a fundamental effect at the particle level, but an emergent macroscopic phenomenon that appears in large condensed aggregates. A brief sketch of the analysis that leads to the derivation of the electromagnetic vacuum contribution to the inertia reaction force is presented, in several complementary ways and also in a fully covariant way. All derivations were initially done within Stochastic Electrodynamics and more recently, we briefly report here for the first time, they have been reformulated within ordinary Quantum Electrodynamics. Analysis leading to an expression for, what we can call, the vacuum electromagnetic field contribution to the inertia reaction force, is briefly reviewed. As an example, the case of an ordinary electromagnetic (microwave) cavity is briefly mentioned with its associated very small but nonnegligible inertial mass of the interior of the microwave cavity case (i.e., the cavity alone not considering its walls). Next, it is briefly mentioned that the results for inertial mass can be passed to passive gravitational mass. Thus some light is thrown on the origin of the Weak Equivalence Principle, which equates inertial mass to passive gravitational mass. Finally we mention the derivation of Newton's gravitational force expression that easily follows from this analysis. Unfortunately, all this has been accomplished just for the electromagnetic vacuum case, as contribution by the other quantum vacuum fields have not been calculated. This specially refers to the gluonic vacuum, which presumably contributes the lion's share of the inertia reaction force in ordinary objects. Furthermore, the origin of what constitutes active gravitational mass has still not been considered within this approach. I.e., why a massive object “bends” space-time still remains unexplained.

The experiment PVLAS studies the optical properties of the vacuum, that behaves much like a material medium when it is permeated by an external (electric or magnetic) field. Using a strong superconducting magnet and a very sensitive ellipsometer we have searched for modifications of the index of refraction of the vacuum due to the presence of a magnetic field. A birefringence is predicted to arise because of the vacuum fluctuations of the electromagnetic field, and a similar effect (dichroism) could be due to the presence of yet undiscovered low mass particles interacting with two photons.

At present PVLAS has set the best existing limits on such processes, its sensitivity being limited by external noise sources which have now been accounted for. A completely redesigned prototype apparatus is now under construction: it is based on rotating permanent magnets and an ellipsometer employing an ultra stable Fabry-Perot resonator. A 50-fold improvement in the sensitivity of the ellipsometer has now been achieved, and we hope to improve our best limits when the magnets system will be installed.

Little is known about the physics frontier of strong acceleration; both classical and quantum physics need further development in order to be able to address this newly accessible area of physics. In this lecture we discuss what strong acceleration means and possible experiments using electron-laser collisions and, data available from ultra-relativistic heavy ion collisions. We review the foundations of the current understanding of charged particle dynamics in presence of critical forces and discuss the radiation reaction inconsistency in electromagnetic theory and the apparent relation with quantum physics and strong field particle production phenomena. The role of the quantum vacuum as an inertial reference frame is emphasized, as well as the absence of such a ‘Machian’ reference frame in the conventional classical limit of quantum field theory.

The electron vacuum fluctuations measured by do not vanish in an externally applied electric field ε. For an exactly constant field, that is for vacuum uctuations in presence of a constant accelerating force, we show that has a Boson-like structure with spectral state density tanh⁻¹(E/m) and temperature TM = eε/mπ = a_υ/π. Considering the vacuum uctuations of ‘classical’ gyromagnetic ratio g = 1 particles we find Fermi-like structure with the same spectral state density at a smaller temperature T₁ = a_υ/2π which corresponds to the Unruh temperature of an accelerated observer.

Mass is one of the most important concepts in physics and its real understanding represents the key for the formulation of any consistent physical theory. During the past years, a very interesting model of inertial and gravitational mass as the result of the reaction interaction between the charged particles (electrons and quarks) contained in a given body and a suitable “fraction” of QED Zero Point Fields confined within an ideal resonant cavity, associated to the same body, has been proposed by Haish, Rueda and Puthoff. More recently, the author showed that this interpretation is consistent with a picture of mass (both inertial and gravitational) as the seat of ZPF standing waves whose presence reduces quantum vacuum energy density inside the resonant cavity ideally associated to the body volume. Nevertheless so far, the ultimate physical origin of such resonant cavity as well as the mechanism able to “select” the fraction of ZPF electromagnetic modes interacting within it, remained unrevealed. In this paper, basing on the framework of QED coherence in condensed matter, we'll show mass can be viewed as the result of a spontaneous superradiant phase transition of quantum vacuum giving rise to a more stable, energetically favored, macroscopic quantum state characterized by an ensemble of coherence domains, “trapping” the coherent ZPF fluctuations inside a given volume just acting as a resonant cavity. Our model is then able to explain the “natural” emergence of the ideal resonant cavity speculated by Haish, Rueda and Puthoff and its defining parameters as well as the physical mechanism selecting the fraction of ZPF interacting with the body particles. Finally, a generalization of the model to explain the origin of mass of elementary particles is proposed also suggesting a new understanding of Compton's frequency and De Broglie's wavelength. Our results indicates both inertia and matter could truly originate from coherent interaction between quantum matter-wave and radiation fields condensed from quantum vacuum and also give novel and interesting insights into fundamental physical questions as, for example, the structure of elementary particles and matter stability.

The possible unification between electromagnetism and gravity is one of greatest challenges in Physics. According to the so-called “Zero-Point Field Inertia Hypothesis” inertia and gravity could be interpreted, through a semi-classical approach, as the electromagnetic reaction force to the interaction between charged elementary particles contained in a body and quantum vacuum fluctuating electromagnetic modes interacting with them. In a late paper this author, sharing this idea as a starting point but moving within the framework of QFT, proposed a novel model in which inertia emerges from a superradiant phase transition of quantum vacuum due to the coherent interaction between matter-wave and em fields quanta. In both the approaches a resonant-type mechanism is involved in describing the dynamic interaction between a body and ZPF in which it is “immersed”. So it is expected that if a change in the related resonance frequency is induced by modifying the boundary conditions as, for example, through the introduction of a strong electromagnetic field of suitable frequency, the inertial and gravitational mass associated to that body will also be modified. In this paper we have shown, also basing on previous results and starting from the assumption that not only inertia but also gravitational constant G could be truly a function of quantum vacuum energy density, that the application of an electromagnetic field is able to modify the ZPF energy density and, consequently, the value of G in the region of space containing a particle or body. This result particularly suggests a novel interpretation of the coupling between electromagnetic and gravitational interaction ruled by the dynamical features of ZPF energy. Apart from its theoretical consequences, this model could also proposes new paths towards the so-called ZPF-induced gravitation with very interesting applications to advanced technology.

Gravitation is still the less understood among the fundamental forces of Nature. The ultimate physical origin of its ruling constant G could give key insights in this understanding. According to the Einstein's Theory of General Relativity, a massive body determines a gravitational potential that alters the speed of light, the clock's rate and the particle size as a function of the distance from its own center. On the other hand, it has been shown that the presence of mass determines a modification of Zero-Point Field (ZPF) energy density within its volume and in the space surrounding it. All these considerations strongly suggest that also the constant G could be expressed as a function of quantum vacuum energy density somehow depending on the distance from the mass whose presence modifies the ZPF energy structure. In this paper, starting from a constitutive medium-based picture of space, it has been formulated a model of gravitational constant G as a function of Planck's time and Quantum Vacuum energy density in turn depending on the radial distance from center of the mass originating the gravitational field, supposed as spherically symmetric. According to this model, in which gravity arises from the unbalanced physical vacuum pressure, gravitational “constant” G is not truly unchanging but slightly varying as a function of the distance from the mass source of gravitational potential itself. An approximate analytical form of such dependence has been discussed. The proposed model, apart from potentially having deep theoretical consequences on the commonly accepted picture of physical reality (from cosmology to matter stability), could also give the theoretical basis for unthinkable applications related, for example, to the field of gravity control and space propulsion.

Sonoluminescence, or its more frequently studied version known as Single Bubble Sonoluminescence, consisting in the emission of light by a collapsing bubble in water under ultrasounds, represents one of the most challenging and interesting phenomenon in theoretical physics. In fact, despite its relatively easy reproducibility in a simple laboratory, its understanding within the commonly accepted picture of condensed matter remained so far unsatisfactory. On the other hand, the possibility to control the physical process involved in sonoluminescence, representing a sort of nuclear fusion on small scale, could open unthinkable prospects of free energy production from water. Different explanations has been proposed during the past years considering, in various way, the photoemission to be related to electromagnetic Zero Point Field energy dynamics, by considering the bubble surface as a Casimir force boundary. More recently a model invoking Cherenkov radiation emission from superluminal photons generated in quantum vacuum has been successfully proposed. In this paper it will be shown that the same results can be more generally explained and quantitative obtained within a QED coherent dynamics of quantum vacuum, according to which the electromagnetic energy of the emitted photons would be related to the latent heat involved in the phase transition from water's vapor to liquid phase during the bubble collapse. The proposed approach could also suggest an explanation of a possible mechanism of generation of faster than light (FTL) photons required to start Cherenkov radiation as well as possible applications to energy production from quantum vacuum.