Vacuum Field Research Articles

Vortex radiation from a single emitter in a chiral plasmonic nanocavity

Abstract Manipulating single emitter radiation is essential for quantum information science. Significant progress has been made in enhancing the radiation efficiency and directivity by coupling quantum emitters with microcavities and plasmonic antennas. However, there has been a great challenge to generate complex radiation patterns such as vortex beam from a single emitter. Here, we report a chiral plasmonic nanocavity, which provides a strong local chiral vacuum field at an exceptional point. We show that a single linear dipole emitter embedded in the nanocavity will radiate to vortex beam via anomalous spontaneous emission with a Purcell enhancement factor up to ∼1000. Our scheme provides a new field manipulation method for chiral quantum optics and vortex lasers at the nanoscale.

Breakdown Time Characteristics Under Uniform Electric Field in Vacuum

Breakdown waveforms, including breakdown electric field or breakdown voltage and breakdown time, are the most direct and important parameters in the conditioning, which could help to reflect the conditioning process. This article studies the breakdown time characteristics of conditioning with impulse voltage under a uniform electric field in vacuum. The results show that breakdown time moves from the decreasing curve to the rising curve of the impulse voltage waveform in the conditioning process. When conditioning saturation is reached, breakdown time varies in a certain range in the rising curve of the impulse voltage waveform. The breakdown electric field increases during the conditioning and fluctuates in a certain range when conditioning saturation is reached. Breakdown time and breakdown electric field characteristics are explained by breakdown mechanism. Furthermore, a method combining breakdown time and breakdown electric field for conditioning saturation judgment is proposed.

From spatial to temporal patterns: cooperativity across ion channels in supercritical membranes

Theoretically predicted by Fisher and de Gennes in 1978, critical Casimir forces are the thermodynamic analogues of the Casimir-Polder attraction forces due to quantum fluctuations of confined electromagnetic field in vacuum. In the context of lipid membranes close to a miscibility transition, critical Casimir interactions are thought to be responsible for clustering of membrane proteins. Here we explore the hypothesis that these effective statistical-field mediated interactions can explain the observed ion channel cooperativity that has been suggested to promote multistability of the membrane potential and thus “cellular memory”.

Proton deflectometry with in situ x-ray reference for absolute measurement of electromagnetic fields in high-energy-density plasmas.

We report a technique of proton deflectometry that uses a grid and an in situ reference x-ray grid image for precise measurements of magnetic fields in high-energy-density plasmas. A D3He fusion implosion provides a bright point source of both protons and x-rays, which is split into beamlets by a grid. The protons undergo deflections as they propagate through the plasma region of interest, whereas the x-rays travel along straight lines. The x-ray image, therefore, provides a zero-deflection reference image. The line-integrated magnetic fields are inferred from the shifts of beamlets between the deflected (proton) and reference (x-ray) images. We developed a system for analysis of these data, including automatic algorithms to find beamlet locations and to calculate their deflections from the reference image. The technique is verified in an experiment performed at OMEGA to measure a nonuniform magnetic field in vacuum and then applied to observe the interaction of an expanding plasma plume with the magnetic field.

Ultrafast modulation of vibrational polaritons for controlling the quantum field statistics at mid-infrared frequencies

Controlling the quantum field statistics of confined light is a long-standing goal in integrated photonics. We show that by coupling molecular vibrations with a confined mid-infrared cavity vacuum, the photocount and quadrature field statistics of the cavity field can be reversibly manipulated over sub-picosecond timescales. The mechanism involves changing the cavity resonance frequency through a modulation of the dielectric response of the cavity materials using femtosecond UV pulses. For a single anharmonic molecular vibration in an infrared cavity under ultrastrong coupling conditions, the pulsed modulation of the cavity frequency can adiabatically produce mid-infrared light that is simultaneously sub-Poissonian and quadrature squeezed, depending on the dipolar behavior of the vibrational mode. For a vibration-cavity system in strong coupling, non-adiabatic polariton excitations can be produced after the frequency modulation pulse is over, when the system is initially prepared in the lower polariton state. We propose design principles for the generation of mid-infrared quantum light by analyzing the dependence of the cavity field statistics on the shape of the electric dipole function of the molecule, the cavity detuning at the modulation peak and the anharmonicity of the Morse potential. Feasible experimental implementations of the modulation scheme are suggested. This work paves the way for the development of molecule-based mid-infrared quantum optical devices at room temperature.

4D Einstein-Gauss-Bonnet gravity from non-Einsteinian phase

We set up an Einstein-Gauss-Bonnet theory in four dimensions, based on the recent formulation of pure gravity with extra dimensions of vanishing metrical length [1]. In absence of torsion, the effective field equations depend only on the four-metric, reflecting a quadratic curvature nonlinearity but no higher than second order derivatives. In contrast with recent proposals to obtain 4dEGB theories through a singular rescaling of the Gauss-Bonnet coupling, this formalism requires no (classical) regularization of divergences and is inequivalent to Horndeski gravity, while being generally covariant and independent of compactification. Notably, the vacuum field equations admit FLRW cosmologies containing nonsingular bounce and self-accelerating Universe, and spherically symmetric black holes more general than Schwarzschild. The quadratic theory of gravity emerging here is shown to be preserved against the inclusion of higher Lovelock densities in 5+2n dimensions.

Nanoscale Vacuum Field Emission Triode With a Double Gate Structure

A planar lateral Vacuum Field Emission Triode (VFET) with a double gate structure is proposed to improve the gate modulation characteristics in this letter. The preparation of this double gate structure is obtained by using the mature bottom gate VFET manufacturing process without any additional dedicated masks. The emission characteristics of the fabricated VFET under vacuum and atmosphere condition are measured. The experimental results demonstrate that both the bottom gate and the top gate can effectively control the emission electrons in the vacuum channel with width of about 110–200 nm which is successfully prepared by the electro-forming process. The operating mechanism of the device is basically the same as that of the plane-bottom gate VFET, and the device has achieved good field electron emission characteristics and double-gate modulation characteristics. Meanwhile, the vacuum channel is covered by the top gate insulator layer, which relaxing the vacuum requirement and improving the collection efficiency of emitted electrons by drain electrode about 50% in air.

CFD SIMULATIONS AND ANALYSES OF ASYMPTOMATIC AND SYMPTOMATIC NASAL AIRWAY OBSTRUCTIONS

The numerical simulations of the flow in nasal airways were performed for two different clinical cases. The results comprised the distributions of scalars at five different sections and included contours of pressure, velocity magnitude, turbulent kinetic energy and vorticity magnitude. Simulations showed the air branching occurring at the inferior meatus is unaffected by the variations in the volumetric flow rate or the changes in the flow regime through the olfactory cleft. However, the contractions and the following rapid change in the cross-section of the nasopharynx preclude the upward penetration of the vacuum field set by the lungs during the inhalation process. As a result, considerably low velocities and significant cross-sectional nonuniformities are observed, which lead to the appearances of the secondary flow structures and strong unsteadiness. Increased interactions between the airflow and the walls of the nasal cavity resulted in an increase in the vorticity on the right middle meatus and upper inferior meatus. The vorticity was also very high in the nostrils, where the flow was not fully developed.

Adjoint methods for quasi-symmetry of vacuum fields on a surface

Adjoint methods can speed up stellarator optimisation by providing gradient information more efficiently compared with finite-difference evaluations. Adjoint methods are herein applied to vacuum magnetic fields, with objective functions targeting quasi-symmetry and a rotational transform value on a surface. To measure quasi-symmetry, a novel way of evaluating approximate flux coordinates on a single flux surface without the assumption of a neighbourhood of flux surfaces is proposed. The shape gradients obtained from the adjoint formalism are evaluated numerically and verified against finite-difference evaluations.

Freeze-thaw vacuum treatment of landfill sludge: Mechanism of uneven frost heaving and dewatering performance

The method of freeze-thaw combined with vacuum pretreatment for landfill sludge (LS) has attracted extensive attention. However, most of the existing approaches are based on small-scale laboratory testing, and further testing studies must be performed to realize in situ treatment. To enhance the practicality of such approaches, the range of temperature effects on LS was analysed after field freeze-thaw model testing. After the freeze-thaw model test, samples were transported to the laboratory for unidirectional oedometer tests, and the remaining samples were retained in the field to continue vacuum model testing for exploring the differences in the consolidation and drainage effect of the LS. Results show that temperature changes during freeze-thaw process affect the distribution of sludge and water in the model boxes, resulting in frost heave and the appearance of “extrusion rings”. In addition, the coefficient of consolidation obtained from the unidirectional oedometer test shows that the consolidation coefficient is generally larger near the freezing tubes at a lower temperature. The settlement determined from the field vacuum preloading test shows that the subsequent vacuum consolidation settlement is larger at the position with a lower elevation of the frozen sludge surface. The comparison indicates that the consolidation and drainage effect in the field is not as significant as that in the laboratory. The findings can provide reference to optimize the field conditions during the in situ engineering practice of sludge treatment.

Quantum framework for describing retarded and nonretarded molecular interactions in external electric fields

We employ various quantum-mechanical approaches for studying the impact of electric fields on both nonretarded and retarded noncovalent interactions between atoms or molecules. To this end, we apply perturbative and non-perturbative methods within the frameworks of quantum mechanics (QM) as well as quantum electrodynamics (QED). In addition, to provide a transparent physical picture of the different types of resulting interactions, we employ a stochastic electrodynamic approach based on the zero-point fluctuating field. Atomic response properties are described via harmonic Drude oscillators - an efficient model system that permits an analytical solution and has been convincingly shown to yield accurate results when modeling non-retarded intermolecular interactions. The obtained intermolecular energy contributions are classified as field-induced (FI) electrostatics, FI polarization, and dispersion interactions. The interplay between these three types of interactions enables the manipulation of molecular dimer conformations by applying transversal or longitudinal electric fields along the intermolecular axis. Our framework combining four complementary theoretical approaches paves the way toward a systematic description and improved understanding of molecular interactions when molecules are subject to both external and vacuum fields.

The Physics behind the NASA Flyby Anomaly

From 1990 to 2005 NASA did six flybys of Earth in order to boost the energy of each spacecraft, enabling them to go deeper into the solar system. These six flybys showed an unexpected violation in the conservation of energy of up to 100 sigmas, matching a simple physical formula related to the input and output spacecraft velocities relative to the Earth rotational plane. Mysteriously, occasionally the effect was not present. After several years of reviewing the data and evaluating all sources of perturbation known to NASA, no solution was identified. NASA sent the final report to the author above for further review. Independently, the author’s firm Optical Physics Company had published research into the vacuum field, finding that it was not constant but varied across the Earth’s orbit and was also separately detected being radiated by the Sun. The physics we had learned was applied to the NASA passes, allowing all the anomalies they had encountered to be explained and adding considerably to our understanding of the vacuum field. We hypothesized a radially emitted vacuum field (which controls the rate of time) would couple the radial direction r with time t to add a gtr term in the metric tensor. We then combined the previously published experimental data of the vacuum field radiated by the Sun with the NASA data to develop a formula for the emission of the vacuum field from warm rotating bodies, accurate to about 1%. 25 candidate formulas were evaluated, based on powers of radial acceleration and temperature, and one was definitively selected. This research offers a linkage between the vacuum field whose spectrum is proportional to h and an effect on the metric tensor of gravity. Since both gravity and h control time rates, it seemed credible they could both affect the metric tensor.

Quantum mechanics: how to use Everett theory practically

Among theories of the physical world, quantum mechanics remains a topic of lively discussions on its so-called interpretation. For some it remains an open question to understand how deterministic equations of this theory, as established long ago, may combine with a fundamental uncertainty. We consider the process of spontaneous emission by an atom interacting with infinite number of degrees of freedom of the electromagnetic field. There is uncertainty in the evolution of the photo-emission process which was characterized as Markovian by using the equations of quantum mechanics when the decay of the atom is due to the coupling with the vacuum field. The Markovian property leads us naturally to describe spontaneous emission by using the classical Kolmogorov equation for the probability evolution of a parameter defining the state of the atom. We explain that Everett’s many-worlds interpretation weld together our description, and appears therefore as a consequence of the equations of quantum mechanics, that solves in this case the riddle of deterministic equations describing random events.

Development, construction and tests of the Mu2e electromagnetic calorimeter mechanical structures

The “muon-to-electron conversion” (Mu2e) experiment at Fermilab will search for the charged lepton flavour violating neutrino-less coherent conversion of a muon into an electron in the field of an aluminum nucleus. The observation of this process would be the unambiguous evidence of the existence of physics beyond the standard model. Mu2e detectors comprise a straw-tracker, an electromagnetic calorimeter and an external veto for cosmic rays. In particular, the calorimeter provides excellent electron identification, a fast calorimetric online trigger, and complementary information to aid pattern recognition and track reconstruction. The detector has been designed as a state-of-the-art crystal calorimeter and employs 1348 pure Cesium Iodide (CsI) crystals readout by UV-extended silicon photosensors and fast front-end and digitization electronics. A design consisting of two identical annular matrices (named “disks”) positioned at the relative distance of 70 cm downstream the aluminum target along the muon beamline satisfies the Mu2e physics requirements. The hostile Mu2e operational conditions, in terms of radiation levels (total expected ionizing dose of 12 krad and a neutron fluence of 5 × 1010 n/cm2 @ 1 MeVeq (Si)/y), magnetic field intensity (1 T) and vacuum level (10−4 Torr) have posed tight constraints on scintillating materials, sensors, electronics and on the design of the detector mechanical structures and material choice. The support structure of each 674 crystal matrix is composed of an aluminum hollow ring and parts made of open-cell vacuum-compatible carbon fiber. The photosensors and front-end electronics for the readout of each crystal are inserted in a machined copper holder and make a unique mechanical unit. The resulting 674 mechanical units are supported by a machined plate of vacuum-compatible plastic material. The plate also integrates the cooling system made of a network of copper lines flowing a low temperature radiation-hard fluid and placed in thermal contact with the copper holders to constitute a low resistance thermal bridge. The data acquisition electronics are hosted in aluminum custom crates positioned on the external lateral surface of the disks. The crates also integrate the electronics cooling system as lines running in parallel to the front-end system. In this paper we report on the calorimeter mechanical structure design, the mechanical and thermal simulations that have determined the design technological choices, and the status of component production, quality assurance tests and plans for assembly at Fermilab.

A New Theory for the Essence and Structure of the Photon

A photon is the smallest discrete amount or quantum of electromagnetic radiation, and it is the basic unit of light. It exhibits no shape, “point particle,” according to the standard model of particle physics, meaning that a photon interacts as if it is entirely located at a single point in space and does not spread out to fill a three-dimensional volume. In this study, a new theory, in which the photon demonstrates a structure and shape, is proposed based on the perturbed quantum superfluid field (vacuum) in the photon epoch during the first seconds of the Big Bang. Photons are the nonlinear manifestation of Kelvin–Helmholtz instability that induces the formation of elliptical vortices, known as Kida vortices, which are converted to a three-dimensional spheroidal structure that remains unchanged in time and rotates with uniform angular velocity due to Coriolis force. Using hydrodynamics laws and applying them to a superfluid vacuum, the basic properties of the photon are described. Moreover, this study provides mathematical models to calculate the kinetic energy, radius, volume, charge, and particle-wave duality of photon. To confirm the proposed theory, the mathematical formulations are presented. We conclude that the photon shape is accessible to human imagination; knowing this shape helps determine photon properties and sheds light on how matter is made as well as explains the interactions of subatomic particles.

Energy Basic State Field of the Universe (I)

This paper proposes the hypothesis that cosmic vacuum is full of energy basic state field (EBSF), and expounds its physical connotation based on cosmological constant of general relativity and Dirac’s negative energy sea. Cosmic vacuum is a special kind of physical object with complexity that can be characterized by quantum super-fluidity; it forms Dark energy in Universe. The rationality and correctness of this hypothesis are demonstrated through the analysis in terms of energy basic distribution on the background of cosmic scale and energy scale, quantum vacuum field, the evolution of EBSF state into static quantum’s state (particles or quasiparticle) and so on. Also it estimates the vacuum energy value in the energy basic state field to the same order of energy as the energy value for driving the accelerated expansion of the universe.

Primordial Weibel instability

We study the onset of vector instabilities in the post-inflationary epoch of the Universe as a mechanism for primordial magnetic fields amplification.We assume the presence of a charged spectator scalar field arbitrarily coupled to gravity during Inflation in its vacuum de Sitter state. Gravitational particle creation takes place at the transition from Inflation to the subsequent Reheating stage and thus the vacuum field state becomes an excited many particles one.Consequently this state can be described as a real fluid, and we build out the hydrodynamic framework using second order theories for relativistic fluids with a relaxation time prescription for the collision integral.Given the high-temperature regime and the vanishing scalar curvature of the Universe during Reheating (radiation-dominated-type era), the fluid can be regarded as a conformal one.The large quantum fluctuations induced by the rapid transition from inflationary to effectively radiation dominated expansion become statistical fluctuations whereby both a charge excess and anisotropic pressures are produced in any finite domain. The precise magnitude of the effect for each scale is determined by the size of the averaging domain and the coupling to curvature. We look at domains which are larger than the horizon at the beginning of Reheating, but much smaller than our own horizon, and show that in a finitefraction of them the anisotropy and charge excess provide suitable conditions for a Weibel instability. If moreover the duration of reheating is shorter than the relaxation time of the fluid, then this instability can compensate or even overcome the conformal dilution of a primordial magnetic field. We show that the non-trivial topology of the magnetic field encoded in its magnetic helicity is also amplified if present.

Cavity catalysis: modifying linear free-energy relationship under cooperative vibrational strong coupling.

Here, we used an unconventional idea of cooperative vibrational strong coupling of solute and solvent molecules to enhance the rate of an esterification reaction. Different derivatives of p-nitrophenyl benzoate (solute) and isopropyl acetate (solvent) are cooperatively coupled to an infrared Fabry–Perot cavity mode. The apparent rates are increased by more than six times at the ON resonance condition, and the rate enhancement follows the lineshape of the vibrational envelope. Very interestingly, a strongly coupled system doesn't obey the Hammett relations. Thermodynamics suggests that the reaction mechanism remains intact for cavity and non-cavity conditions. Temperature-dependent experiments show an entropy-driven process for the coupled molecules. Vacuum field coupling decreases the free energy of activation by 2–5 kJ mol−1, supporting a catalysis process. The non-linear rate enhancement can be due to the reshuffling of the energy distribution between the substituents and the reaction center across the aromatic ring. These findings underline the non-equilibrium behavior of cavity catalysis.

Dynamical fermions, centre vortices, and emergent phenomena

The non-trivial ground-state vacuum fields of QCD form the foundation of matter. Here we examine the centre vortices identified within the ground-state fields of lattice QCD. We aim to understand the manner in which dynamical fermions in the QCD vacuum alter the centre-vortex structure. Using modern visualisation techniques, the centre-vortex structure of pure-gauge and dynamical-fermion fields is quantified and compared. We then explore the impact this modified structure has on measures of confinement and dynamical mass generation. The string tension of the static quark potential, positivityviolation in the gluon propagator, and dynamical mass generation in the overlap quark propagator are of particular interest. The impact of dynamical fermions is significant and provides new insights into the role of centre vortices in underpinning both confinement and dynamical chiral symmetry breaking in QCD.

Nonlinear cooperative transfer of atomic energy in the vacuum field of the cavity

This paper researches the nonlinear cooperative transfer of atomic energy in the vacuum field of the cavity. Many scientists are concerned about a more detailed study of the cooperation interactions between different subsystems of quantum processes. Based on the theory of resonant interaction with two photons, between two active dipole atoms and a forbidden dipole in resonance with two photons, the author examines for the first time the resonance effect in two ways of the cavity. In some situations, the so-called quantum inseparability needs a new redefinition in order to describe the process that occurs between the photons belonging to these two modes of the cavity. In such a situation, it is better to study the quantum properties of collective modes arising from nonlinear interactions between traditional modes of the electromagnetic field cavity.