Classical Vacuum Research Articles

Entanglement and Generalized Berry Geometrical Phases in Quantum Gravity

A new formalism is introduced that makes it possible to elucidate the physical and geometric content of quantum space–time. It is based on the Minimum Group Representation Principle (MGRP). Within this framework, new results for entanglement and geometrical/topological phases are found and implemented in cosmological and black hole space–times. Our main results here are as follows: (i) We find the Berry phases for inflation and for the cosmological perturbations and express them in terms of the observables, such as the spectral scalar and tensor indices, nS and nT, and the tensor-to-scalar ratio r. The Berry phase for de Sitter inflation is imaginary with the sign describing the exponential acceleration. (ii) The pure entangled states in the minimum group (metaplectic) Mp(n) representation for quantum de Sitter space–time and black holes are found. (iii) For entanglement, the relation between the Schmidt type representation and the physical states of the Mp(n) group is found: This is a new non-diagonal coherent state representation complementary to the known Sudarshan diagonal one. (iv) Mean value generators of Mp(2) are related to the adiabatic invariant and topological charge of the space–time, (matrix element of the transition −∞<t<∞). (v) The basic even and odd n-sectors of the Hilbert space are intrinsic to the quantum space–time and its discrete levels (in particular, continuum for n→∞), they do not require any extrinsic generation process such as the standard Schrodinger cat states, and are entangled. (vi) The gravity or cosmological on one side and another of the Planck scale are entangled. Examples: The quantum primordial trans-Planckian de Sitter vacuum and the classical late de Sitter vacuum today; the central quantum gravity region and the external classical gravity region of black holes. The classical and quantum dual gravity regions of the space–time are entangled. (vii) The general classical-quantum gravity duality is associated with the Metaplectic Mp(n) group symmetry which provides the complete full covering of the phase space and of the quantum space–time mapped from it.

Analysis of the limits of applicability of photomultiplier as part of a laser Doppler anemometer

This paper considers the use of laser Doppler anemometry methods for non-contact measurement of the velocity of a moving medium in various phase states. It notes the specifi city of conditions of application of laser Doppler anemometers, in that in a number of cases there are restrictions on the use of photomultipliers. In order to find an alternative to the classic photomultiplier of a laser Doppler anemometer, three types of photomultipliers were investigated: classic electric vacuum; silicon avalanche multipixel; with microchannel plate. Physical experiments were conducted to measure the velocity of aero- and hydrodynamic fl ows by laser Doppler anemometer with photomultipliers of three types. The velocities of a rotating glass disk, aerodynamic fl ow in a channel of rectangular cross-section, and aerosol flow, as well as hydrodynamic flooded jet, were measured. The obtained experimental data were analyzed according to the criteria for assessing the quality (efficiency) of operation and finding the limits of applicability of the specified photomultipliers. Based on the physical properties of the studied photomultipliers, their efficiency indicators in various experiments are explained. The boundaries of the effective use of these photomultipliers in a wide class of physical experiments are determined. The results obtained are important for researchers involved in the study of aero- and hydrodynamic flows, where accurate and reliable measurements of flow velocity are required. The choice of an optimal photomultiplier tube for the laser anemometer allows increasing the accuracy and ease of obtaining experimental data and reducing the cost of the final equipment.

The rise and fall of the Standard-Model Higgs: electroweak vacuum stability during kination

In this paper we investigate the vacuum stability of the non-minimally coupled Standard-Model Higgs during a phase of kinetic domination following the end of inflation. The non-minimal coupling to curvature stabilises the Higgs fluctuations during inflation while driving them towards the instability scale during kination, when they can classically overcome the potential barrier separating the false electroweak vacuum from the true one at super-Planckian field values. Avoiding the instability of the Standard-Model vacuum sets an upper bound on the inflationary scale that depends both on the strength of the non-minimal interaction and on the top quark Yukawa coupling. Classical vacuum stability is guaranteed if the gravitationally-produced energy density is smaller than the height of barrier in the effective potential. Interestingly enough, thanks to the explosive particle production in the tachyonic phase, the Higgs itself can be also appointed to the role of reheaton field responsible for the onset of the hot Big Bang era, setting an additional lower bound on the inflationary scale Hinf\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\mathcal{H}}_{\ extrm{inf}} $$\\end{document} ≳ 105.5 GeV. Overall, these constraints favour lower masses for the top quark, in agreement with the current measurements of the top quark pole mass. We perform our analysis semi-analytically in terms of the one-loop and three-loop running of the Standard-Model Higgs self-coupling and make use of lattice-based parametric formulas for studying the (re)heating phase derived in arXiv:2307.03774. For a specific choice of mt = 171.3 GeV we perform also an extensive numerical scanning of the parameter space via classical lattice simulations, identifying stable/unstable regions and supporting the previous analytical arguments. For this fiducial value, the heating of the Universe is achieved at temperatures in the range 10−2–109 GeV.

Mass generation via nonlinear massive solution in Higgs potential and particle creations

The nonlinear massive plane wave solution of the classical scalar field in the Higgs potential is revisited to study the mass generation and particle creation. In particular, by assuming that the Higgs system is in the slightly excited state in early universe and it is described by the nonlinear solution, we study the mass generation mechanism for massive vector bosons and a heavy fermion in the quantum field theory around the nonlinear massive classical field. The nonlinear massive classical solution gives the transition from the vacuum to a pair of vector bosons and fermions. We present the new formulae of the probability density of the production process for particles in the standard model of elementary particle physics. The probability densities of the particle productions vanish when the nonlinear massive solution reduces to the constant solution (the classical vacuum expectation value); while the probability densities are expressed as the function of the free parameter in the classical solution in general case. We discuss the behavior of the probability densities for the three oscillating modes in the classical solution.

How large is the space of covariantly constant gauge fields

The covariantly constant gauge fields are solutions of the sourceless Yang-Mills equation and represent classical vacuum fields. We found that the moduli space of the covariantly constant gauge fields is infinite-dimensional and is therefore much larger than the space of constant chromomagnetic fields. These solutions represent a space lattice of non-perturbative magnetic flux tubes/vertices oriented in the opposite directions, each of which has a Dirac quantum flux. The geometrical structure of the solutions is self-sustaining without presence of any Higgs field support. They are similar to a condensate of the Nielsen-Olesen magnetic flux tubes of opposite orientations. The solutions have a non-vanishing Hopf invariant density.

Covariantly constant Yang Mills vacuum fields and condensation of magnetic fluxes

Covariantly constant gauge fields are solutions of the sourceless Yang-Mills equation and represent classical vacuum fields. We found that the moduli space of covariantly constant gauge fields is infinite-dimensional and is much larger than the space of constant chromomagnetic fields. These solutions represent non-perturbative chromomagnetic flux tubes (vortices) and are the superposition of Nielsen-Olesen chromomagnetic vortices of opposite orientations. It is suggested that the solutions describe the condensate of superposed tubes (vortices) of opposite orientations and represent a dual analog of the Cooper pairs condensate in a superconductor.

Dipole symmetry breaking and fractonic Nambu-Goldstone mode

We introduce a family of quantum field theories for fields carrying monopole and dipole charges. In contrast to previous realizations, fields have quadratic two-derivative kinetic terms. The dipole symmetry algebra is realized in a discretized internal space and connected to the physical space through a background gauge field. We study spontaneous symmetry breaking of dipole symmetry in 1+1 dimensions in a large-NN limit. The trivial classical vacuum is lifted by quantum corrections into a vacuum which breaks dipole symmetry while preserving monopole charge. By means of a Hubbard-Stratonovich transformation, heat-kernel and large-NN techniques, we compute the effective action for the low-energy modes. We encounter a fractonic immobile Nambu-Goldstone mode whose dispersion characteristics avoid Coleman-Hohenberg-Mermin-Wagner theorem independently of the large-NN limit.

Holography for bulk states in 3D quantum gravity

In this work we discuss the holographic description of states in the Hilbert space of (2+1)-dimensional quantum gravity, living on a time slice in the bulk. We focus on pure gravity coupled to pointlike sources for heavy spinning particles. We develop a formulation where the equations for the backreacted metric reduce to two decoupled Liouville equations with delta-function sources under pseudosphere boundary conditions. We show that both the semiclassical wavefunction and the gravity solution are determined by a universal object, namely a classical Virasoro vacuum block on the sphere. In doing so we derive a version of Polyakov’s conjecture, as well as an existence criterion, for classical Liouville theory on the pseudosphere. We also discuss how some of these results are modified when considering closed universes with compact spatial slices.

On the possibility of classical vacuum polarization and magnetization

It is common practice to take for granted the equality (up to the constant ɛ 0) of the electric displacement (D) and electric (E) field vectors in vacuum. The same happens with the magnetic field (H) and the magnetic flux density (B) vectors (up to the constant ). The fact that gravity may change this by effectively inducing dielectric or magnetic responses to the primary fields is commonly overlooked. It is the purpose of this communication to call attention to classical polarization or magnetization of the vacuum due to the concomitant presence of gravitational and electromagnetic sources. The formalism of differential forms (exterior calculus) is used since it provides a clear-cut way to achieve this. This work offers new routes for possible detection of various spacetime geometries via their electromagnetic manifestations and the way they influence light propagation.

Ultrasonic-mediated electrochemical design of graphene/polyacrylonitrile conductive membrane for antifouling and electrofiltration

Electrofiltration using conductive membranes can effectively alleviate membrane fouling. However, poor dispersion and aggregation in water severely constrain the ability of graphene (Gr) to synthesize conductive membranes. Herein, the water-dispersible Gr with high conductivity is tailored by ultrasonic-assisted electrochemical exfoliation and loaded onto the polyacrylonitrile (PAN) membrane by classical vacuum filtering in layers. The customization at 6 V voltage, 40 W ultrasonic power, and 23.87 g/m2 mass loading endows an optimal improvement in membrane pore structure, permeability, mechanical behavior, and electrochemical properties. The graphene/polyacrylonitrile (Gr/PAN) conductive membrane exhibits a high conductivity of 6.43 S/cm and a water flux of 450.19 L m-2h−1. The membrane shows remarkable antifouling capabilities by achieving a 99.8% rejection rate, 89.74% flow rate recovery, and only 10.26% irreversible fouling using yeast as a pollutant model. The normalized flux of the membrane can stay high at 0.41 after electrofiltration for 120 min, outperforming other conductive membranes in comparison. Cyclic electrofiltration of the developed membrane exhibits a 53.85% higher normalized flux than when no electric field is present, demonstrating its potential for long-lasting antifouling under electric fields. This study offered a novel strategy for the straightforward construction of highly functional graphene-based conductive membranes utilized in electrofiltration.

Nonlinear feedforward enabling quantum computation

Measurement-based quantum computation with optical time-domain multiplexing is a promising method to realize a quantum computer from the viewpoint of scalability. Fault tolerance and universality are also realizable by preparing appropriate resource quantum states and electro-optical feedforward that is altered based on measurement results. While linear feedforward has been realized and become a common experimental technique, nonlinear feedforward was unrealized until now. In this paper, we demonstrate that a fast and flexible nonlinear feedforward realizes the essential measurement required for fault-tolerant and universal quantum computation. Using non-Gaussian ancillary states, we observed 10% reduction of the measurement excess noise relative to classical vacuum ancilla.

Design of a Vacuum Independent, Power Assisted Brake by Wire System using a Novel Electro-Magnetic Brake Booster

With an increasing demand in the market towards electrical vehicles through technological advancements in the automotive field like, automated driving assistance that which have resulted in higher safety requirements and new innovations in the braking system, such as vacuum-independent, automated braking, and regenerative braking, play a crucial role in the vehicle's comfort and economics. However, the classic vacuum brake booster is no longer capable of meeting these requirements. A revolutionary Electro-Magnetic brake booster system is suggested in this research; this system is aimed to perform the function of boosting or enhancing the driver's pedal power despite remaining dependent on the vacuum source. Such an Electro-magnetic brake booster is mainly composed of an Electro-magnetic core plate, a ferromagnetic actuating plate and an ECU. It consumes electrical energy and converts into magnetic force to attract the metallic actuating plate, which is mechanically coupled to the pushrod of the master cylinder. However, the power required for braking (developing pressure in a master cylinder) is provided by the electrical power source. The core plate is associated with a pole as the electromagnet cores are mounted on one side of it. By incorporating a pedal pressure sensor linked to the ECU, which can control the electric power input to this core plate. Thus, the magnetic force developed is used in pulling the Actuating plate. In turn, it builds up the required pressure in the master cylinder. This novel Electro-Magnetic brake booster can be a better solution to satisfy the drawbacks of the existing brake boosters such as complexity in the structure and mechanism. Thus, this brake booster can be joined in substantial vehicles, autos and can be utilized as driver brake assistance for future Electric Vehicles by making a few upgrades in the ECU and the servo.
 

Improvement of the manufacturing method of multi-component paste-like vegetable semi-finished products with a high degree of readiness

The object of the study is a multi-component past-like semi-finished product based on apples, Jerusalem artichokes, cranberries and hawthorn, which are natural nutrients with original properties obtained by cooking at 55–60 °C in an experimental vacuum-evaporator. The method of production of a multi-component semi-finished product has been improved by keeping hawthorn in a 10...15 % NaCl solution with the addition of 1 % citric acid at 20...25 °C for 30...45 minutes. Blanching with hot steam at a temperature of 105...110 °C is carried out for: apple (2...3 min), Jerusalem artichoke (5...8 min) and hawthorn (4...6 min), and cranberries are blanched with water for 1.5...3 min at temperatures of 80...90 °C. Wiping the components followed by recipe-component blending and boiling at 55...60 °C in an experimental vacuum-evaporator. According to the organoleptic parameters, the puree blend containing: apple – 35 %, Jerusalem artichoke – 30 %, cranberry – 25 % and hawthorn – 10 % with a yellow-orange color has the advantage. The ultimate shear stress (pureed components, Pa) is: apple – 14, Jerusalem artichoke – 322, cranberry – 75, hawthorn – 445. The boiled paste mixture has an increased viscosity by 3.5 times compared to the control. The heating of the working chamber and the stirrer of the vacuum-evaporating apparatus is carried out by a film resistive electronic heater of the radiating type, providing stabilization of the temperature effect and a 45 % increase in the boiling efficiency compared to the classic vacuum apparatus. The improved method will expand the range of competitive semi-finished products of a wide range of applications with natural nutrients and regulated rheological and functional properties, which will contribute to the production of food products with an immunomodulating effect

Quantum instability of gauge theories on κ -Minkowski space

We consider a gauge theory on the 5-d $\kappa$-Minkowski which can be viewed as the noncommutative analog of a $U(1)$ gauge theory. We show that the Hermiticity condition obeyed by the gauge potential $A_\mu$ is necessarily twisted. Performing a BRST gauge-fixing with a Lorentz-type gauge, we carry out a first exploration of the one loop quantum properties of this gauge theory. We find that the gauge-fixed theory gives rise to a non-vanishing tadpole for the time component of the gauge potential, while there is no non-vanishing tadpole 1-point function for the spatial components of $A_\mu$. This signals that the classical vacuum of the theory is not stable against quantum fluctuations. Possible consequences regarding the symmetries of the gauge model and the fate of the tadpole in other gauges of non-covariant type are discussed.

Product manifolds as realizations of general linear symmetries

This paper considers the relationship between geometry, symmetry and fundamental interactions — gravity and those mediated by gauge fields. We explore product spacetimes which (a) have the necessary symmetries for gauge interactions and four-dimensional gravity and (b) reduce to an [Formula: see text]-dimensional isotropic universe in their flat space limit. The key technique is looking at orbits of the operator form of symmetric rank-two tensors under changes of coordinate system. Orbits containing diagonal matrices are seen to correspond to product manifolds. The [Formula: see text] symmetry of the decompactified universe acts nonlinearly on such a product spacetime. We explore the resulting Kaluza–Klein theories, in which the internal symmetries act indirectly on space of the extra dimensions, and give two examples: a six-dimensional model in which the gauge symmetry is [Formula: see text] and a seven-dimensional model in which it is [Formula: see text]. We identify constraints that can be placed on any rank-two symmetric tensor to obtain such spacetimes: relationships between polynomial invariants. The multiplicities of its eigenvalues determine the dimensionalities of the factor spaces and hence the gauge symmetries. If the tensor in question is the Ricci tensor, other than two-dimensional factor spaces all the factor spaces are Einstein manifolds. This situation represents the classical vacuum of the Kaluza–Klein theory.

The Synergistic Effect of the Laser Beam on the Thermionic Vacuum Arc Method for Titanium-Doped Chromium Thin Film Deposition

Laser-Induced Thermionic Vacuum Arc (LTVA) provides a better way to produce uniform metallic thin films than the classical Thermionic Vacuum Arc (TVA) method. In Ti-doped chromium thin films produced using LTVA, the amorphous chromium is superimposed with small bcc chromium nanoparticles. These amorphous/crystalline structures with small crystallites induce lower roughness and electrical resistivity, reducing electron–phonon scattering and increasing charge transport across LTVA thin films. A significant shift in resistivity for the LTVA samples is observed due to electron scattering on the phonon–crystalline structures in the TVA samples which exhibit larger crystallites. Meanwhile, the wettability measurements reveal a higher contact angle, resulting in a lower surface free energy and consecutively lower dissociation energy for the LTVA-produced thin films than the TVA samples.

Characterization of selected organometallic compounds by electrospray ionization- and matrix-assisted laser desorption/ionization-mass spectrometry using different types of instruments: Possibilities and limitations.

RationaleOrganometallic compounds are becoming increasingly important in their industrial application as catalysts. Mass spectrometry is an essential tool for the structural confirmation of such organometallics. Because the analysis of this class of molecules can be challenging, the ionization behavior and structural confirmation of selected transition metal catalysts are described in this work.MethodsThe transition metal catalysts investigated were analyzed using classical vacuum MALDI reflectron TOF‐MS as well as intermediate pressure matrix‐assisted laser desorption/ionization quadrupole time‐of‐flight mass spectrometry (MALDI QTOF‐MS). Obtained mass spectra were compared with electrospray ionization MS (ESI‐MS) already established for organometallic compounds, utilizing a QTOF mass spectrometer here. In addition, various sample preparations, including two selected MALDI matrices (trans‐2‐[3‐(4‐tert‐butylphenyl)‐2‐methyl‐2‐propenylidene]malononitrile and 2,2′:5′,2″‐terthiophene) with different solvent combinations for MALDI‐MS measurements, were investigated in detail with respect to their correct isotope distribution of the molecular ions observed.ResultsAll investigated organometallic compounds were successfully identified by vacuum and intermediate pressure MALDI‐MS. Accurate masses of ions related to molecular ion species (e.g., [M‐Cl]+, [M]+, and [M + Na]+) could be determined by MALDI QTOF‐MS measurements with a mass error of less than ±5 ppm for all compounds. Both investigated MALDI matrices performed equally on both instruments. The impact of the analyte/matrix solvent mixtures turned out to be crucial for a successful analysis of the investigated compounds. In contrast, ESI QTOF‐MS yielded masses of ions related to molecular ion species in favorable cases.ConclusionsThe use of MALDI‐MS for the structural confirmation of organometallic compounds is still not widely used. Nevertheless, this work showed that this analytical technique does have some benefits. The analysis of neutral catalysts proves to be quite useful, concluding that this technique provides a complement and/or an alternative to ESI‐MS.

Extending $$\Lambda (t)-$$CDM to the inflationary epoch using dynamical foliations and a pre-inflationary vacuum energy from 5D geometrical vacuum as a unifying mechanism

In this paper assuming a 5D quantum pre-inflationary vacuum energy, we propose a manner to extend some \(\Lambda (t)\)-CDM models to the inflationary period by using dynamical foliations of the five-dimensional (5D) Ricci-flat space-time manifold, regarding a non-compact extra space-like coordinate. In this formalism, we achieve also a geometrical unification of inflation and the present accelerating epoch. In this approach, inflation is generated by a pre-inflationary quantum vacuum energy that maintains the 5D classical vacuum on cosmological scales. We obtain from geometrical conditions that we can model the presence of the pre-inflationary vacuum energy in 4D as a dynamical cosmological constant. In this model, the 4D inflationary period is governed by a power law expansion and for certain values of some parameters of the model, we obtain an spectral index satisfying \(0.9607\le n_s\le 0.9691\) and a scalar-to-tensor ratio \(r=0.098\), values that fit well according to Planck 2018 results. The 4D inflationary potential is induced for the 5D geometry and the 4D pre-inflationary potential is determined by the model and its contribution is necessary so that \(n_s\) and r can fit the observational data. We also show that in this theoretical framework, the present acceleration in the expansion of the universe can be explained due to a remanent of this pre-inflationary vacuum energy scaled to the present epoch and that its description can be done with the same \(\Lambda (t)\). In this period, we obtain a deceleration parameter in agreement with Planck 2018 data under certain restrictions of the parameters of the model. From the geometrical point of view, \(\Lambda (t)\) is depending on the dynamical foliation of the 5D space-time manifold.

Quantum discrete levels of the Universe from the early trans-Planckian vacuum to the late dark energy

The standard model of the universe is further completed back in time before inflation in agreement with observations, classical-quantum gravity duality and quantum space-time. Quantum vacuum energy bends the space-time and produces a constant curvature de Sitter background. We link de Sitter universe and the cosmological constant to the (classical and quantum) harmonic oscillator. Quantum discrete cosmological levels are found: size, time, vacuum energy, Hubble constant and gravitational (Gibbons-Hawking) entropy from the very early trans-planckian vacuum to the classical today vacuum energy. For each level $n = 0, 1, 2,...$, the two: post and pre (trans)-planckian phases are covered: In the post-planckian universe, the levels (in planck units) are: Hubble constant $H_{n} = {1}/\sqrt{(2n + 1)}$, vacuum energy $\Lambda_{n} = 1/(2n + 1)$, entropy $S_n = (2n + 1)$. As $n$ increases, radius, mass and $S_n$ increase, $H_n$ and $\Lambda_n$ decrease and {\it consistently} the universe {\it classicalizes}. In the pre-planckian (trans-planckian) phase, the quantum levels are: $H_{Qn} = \sqrt{(2n + 1)},\; \Lambda_{Qn} = (2n + 1)/1,\; S_{Qn} = 1/(2n + 1)$, $Q$ denoting quantum. The $n$-levels cover {\it all} scales from the far past highest excited trans-planckian level $n = 10^{122}$ with finite curvature, $\Lambda_Q = 10^{122}$ and minimum entropy $S_Q = 10^{-122}$, $n$ decreases till the planck level $(n = 0)$ and enters the post-planckian phase e.g: $n = 1, 2,...,n_{inflation} = 10^{12},... ,n_{cmb} = 10^{114},...,n_{reoin} = 10^{118},...,n_{today} = 10^{122}$ with the most classical value $H_{today} = 10^{-61}$, $\Lambda_{today} = 10^{-122}$, $S_{today} = 10^{122}$. We implement the Snyder-Yang algebra in this context yielding a consistent group-theory realization of quantum discrete de Sitter space-time, classical-quantum gravity duality symmetry and a clarifying unifying picture.(Abridged)

Holographic JT gravity with quartic couplings

We construct the most general theory of 2D Einstein-dilaton gravity coupled with U(1) gauge fields that contains all the 2-derivative and the 4-derivative interactions allowed by the diffeomorphism invariance. We renormalise the 2D action and obtain the vacuum solution as well as the black hole solution. The vacuum solution in the UV is dominated by Lifshitz2 with dynamical exponent (z = frac{7}{3} ) while on the other hand, the spacetime curvature diverges as we move towards the deep IR limit. We calculate the holographic stress tensor and the central charge for the boundary theory. Our analysis shows that the central charge goes as the inverse power of the coupling associated to 4-derivative interactions. We also compute the Wald entropy for 2D black holes and interpret its near horizon divergence in terms of the density of states. We compare the Wald entropy with the Cardy formula and obtain the eigen value of Virasoro operator (L0) for our model. Finally, we explore the near horizon structure of 2D black holes and calculate the central charge corresponding to the CFT near horizon. We further show that the near horizon CFT may be recast as a 2D Liouville theory with higher derivative corrections. We study the Weyl invariance of this generalised Liouville theory and identify the Weyl anomaly associated to it. We also comment on the classical vacuum structure of the theory.