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Dark energy constitutes 68% of the matter of our universe, which has been successfully used in the standard cosmological model to explain the phenomenon of cosmic acceleration. However, the scholars still have different opinions in the origin of dark energy, making it one of the most important unsolved problems in the modern cosmology. There are several candidates to explain the origin of dark energy, such as vacuum energy, scalar field theory, light pressure, etc. However, all these models are still in debate and we are far from a commonly agreed theory to understand the true nature of dark energy. In this report, we intend to re-explore some fundamental properties and the origin of dark energy from the perspective of thermomass theory in the framework of energy conservation principle. Thermomass theory is a newly developed theory in the field of heat transfer, including some new physical quantities, such as thermomass, thermomass velocity, thermomass energy, etc. Thermomass is the relativistic mass of heat and thermomass energy is the relativistic energy. Based on the thermomass theory, the heat transfer can be understood as the direct flow of thermomass under a certain temperature gradient. Then the principle of fluid mechanics can be used to solve the heat transfer problems and a general heat conduction law has been established. Some non-Fourier heat transfer phenomena under the extreme conditions, such as ultrafast laser heating, ultrahigh heat flux at nanoscales, can be well explained by using the general heat conduction law. Meanwhile, a simplified expression of thermomass energy was defined as entransy. Guided by a minimum entransy dissipation principle, the structure of a complicated heat exchanger network can be optimized to increase the energy efficiency. Both the general heat conduction law and entransy model have been experimentally validated. The thermomass theory have been widely accepted and applied in the field of thermal science. But a question still remains: The thermomass energy dissipates during the heat transfer process, where does it go? Actually, we find an answer that the dissipated thermomass energy is closely related with the dark energy. Under the normal temperature and pressure conditions, the order of magnitude of thermomass and its energy is much smaller than that of the static mass and its energy. In the beginning of the Big Bang, the temperature exceeds 1015°C and the thermomass energy equals to or even is larger than the energy of static mass. According to the energy conservation principle, the energy at high level, i.e., electrical energy, optical energy, mechanical energy, etc., will dissipate into the energy at low level, i.e., heat. But in the heat transfer process, heat (thermomass) is conserved, while the thermomass energy will dissipate into a lower level, “invisible” energy. This kind of energy has four features: Filling the whole space, ultra-low energy density, negative pressure and gradually accumulated with time. All these features are in consistence with the performance of dark energy. Hence, we hypothesize that the dark energy comes from the dissipated thermomass energy, which is the motivating force of the cosmic acceleration and forms the main body of our universe.

The geometric phase can be used as a fruitful venue of investigation to infer features of the quantum systems. Its application can reach new theoretical frontiers and imply innovative and challenging experimental proposals. Herein, we take advantage of the geometric phase to sense the corrections induced while a neutral particle travels at constant velocity in front of an imperfect sheet in quantum vacuum. As it is already known, two bodies in relative motion at constant velocity experience a quantum contactless dissipative force, known as quantum friction. This force has eluded experimental detection so far due to its small magnitude and short range. However, we give details of an innovative experiment designed to track traces of the quantum friction by measuring the velocity dependence of corrections to the geometric phase. We notice that the environmentally induced corrections can be decomposed in different contributions: corrections induced by the presence of the dielectric sheet and the motion of the particle in quantum vacuum. As the geometric phase accumulates over time, its correction becomes relevant at a relative short timescale, while the system still preserves purity. The experimentally viable scheme presented would be the first one in tracking traces of quantum friction through the study of decoherence effects on a NV center in diamond., version published in npj quantum informtion 2020

Recent research on superfluid quantum vacuum as the physical origin of universal space has opened new perspectives in astronomy and cosmology. Every stellar object is in the active relation with space and its density diminishes according to the mass-energy equivalence principle. As per Newton’s Shell Theorem, vacuum density is minimum at the surface of the stellar objects and in their centre. The density of space on the surface of the Black holes and in their centre is so low that atoms become unstable. Therefore, they disintegrate back into the elementary particles and cosmic rays. By transforming old matter into these fresh energies, black holes are rejuvenating the universe and keeping its entropy constant.

Based on formal arguments from Zermelo–Fraenkel set theory we develop the environment for explaining and resolving certain fundamental problems in physics. By these formal tools we show that any quantum system defined by an infinite dimensional Hilbert space of states interferes with the spacetime structure M. M and the quantum system both gain additional degrees of freedom, given by models of Zermelo–Fraenkel set theory. In particular, M develops the ground state where classical gravity vanishes. Quantum mechanics distinguishes set-theoretic random forcing such that M and gravitational degrees of freedom are parameterized by extended real line. The large scale smooth geometry compatible with the forcing extensions is one of exotic smoothness structures of $${\mathbb {R}}^4$$ . The amoeba forcing makes the old real line to have Lebesgue measure zero in the extended one. We apply the entire procedure to the cosmological constant problem, especially to discard the zero-modes contributions to the gravitational vacuum density. Moreover, there exists certain exotic smooth $${\mathbb {R}}^4$$ from which one determines the realistic, agreeing with observation, small value of the vacuum energy density.

Introduction: The progress of science at the turn of the 21st century has made it possible to create new quantum engines (QEs), powered by physical vacuum energy. The thrust force generated by QEs can be applied to the vehicle’s body directly, with no transmission required. This will completely transform the transportation industry: the traditional cars will be upgraded with QEs and thus converted into quantomobiles. Ahead of this major transition, we believe it necessary to outline the quantomobile theory. Methods: We formulate and review the key concepts of the quantomobile theory from the systemic, philosophical standpoint, drawing analogies from the existing automobile theory. We also present models of this hypothetical vehicle’s components and functions. Results: The study results in the following: a structure of the quantomobile theory; an overview of the vehicle’s hypothetical configuration, its constructive and operational features, force balance specifics, and movement patterns, along with various aspects of acceleration time, off-road performance, ease of operation, and other features; an analysis of the vehicle’s thrust and speed characteristics that are shaped by the QE thrust. The vertical component of the thrust vector is sufficient both for hovering and pressing down the vehicle. This enables both the airborne and underwater quantocraft modes, transforming the quantomobile into an all-purpose, multi-modal vehicle (multi-modal quantomobile, or MMQ). Discussion: The quantomobile theory, even on the purely hypothetical level, will be of use at the early stages of designing quantomobiles and their subclasses, conducting R&D, developing infrastructure, and supplying the transportation industry with the equipment and HR required.

The nature and origin of the photon and elementary rest masses are some of the challeng-ing problems that physics face. The approaches used to solve these problems are complex and time-consuming. Specifically, the photon rest mass pays attention to theoretical physi-cists. Many experimental works show that the photon rest mass is non zero. This problem can be solved using generalized potential dependent special relativity, which has been de-rived using simple arguments, and Maxwell’s equations, besides the conventional Einstein energy-momentum relation. The results obtained show that the rest mass of photons and elementary particles are strongly dependent on the vacuum energy and a universal con-stant. This result conforms with the models that predict time decaying vacuum energy as-sociated with production of smaller rest mass particles followed by larger masses. The two potential dependent mass expressions conform with the cosmological models that suggest the photon is generated first by assuming the universe consisting of total constant vacuum with decaying cosmological part and mass generating part. Using Maxwell’s equations, beside plank and De Broglie hypothesis together with special relativity energy-momentum relation the photon rest mass is estimated. It was shown that the photon rest mass is ex-tremely small compared to the electron mass.

Radiometric data from the Pioneer 10/11, Galileo and Ulysses spacecraft indicated an anomalous constant acceleration acting on them, directed toward the Sun, and a gradual growth of the radio signal frequency emitted by the receding transmitter. The reported odd acceleration of Pioneer 10 with a magnitude ∼8.5 × 10−10 m/s2 can be explained by an induced gravitational interaction on the S-band signals traveling between the probe and the Earth, arising from the electromagnetic properties of the outer Solar System vacuum zero-point radiation interacting with matter. Their nature is of quantum vacuum origin, and these induced forces act in addition to ordinary gravitational forces, violating the principle of Equivalence. We suggest a new physical theory based on a new principle called “Compensation” as a thinkable explanation for the non-conventional Pioneer effect. The theory of Relation, which is an alternative to the inflationist model, postulates that our universe is made of two antagonistic but complementary structures. The principle of Compensation contradicts Relativity theory, predicts such acceleration and is for the electromagnetic spacetime metric what the principle of Equivalence is for the gravific spacetime metric.

The fact that quantum gravity does not admit an invariant vacuum state has far-reaching consequences for all physics. It points out that space could not be empty, and we return to the notion of an aether. Such a concept requires a preferred reference frame for describing universe expansion and black holes. Here, we intend to find a reference system or class of metrics that could be attributed to ``aether''. We discuss a vacuum and quantum gravity from three essential viewpoints: universe expansion, black hole existence, and quantum decoherence., Comment: 15 pages, 5 figures

Heat transfer in solids is typically conducted through either electrons or atomic vibrations known as phonons. In a vacuum, heat has long been thought to be transferred by radiation but not by phonons because of the lack of a medium1. Recent theory, however, has predicted that quantum fluctuations of electromagnetic fields could induce phonon coupling across a vacuum and thereby facilitate heat transfer2–4. Revealing this unique quantum effect experimentally would bring fundamental insights to quantum thermodynamics5 and practical implications to thermal management in nanometre-scale technologies6. Here we experimentally demonstrate heat transfer induced by quantum fluctuations between two objects separated by a vacuum gap. We use nanomechanical systems to realize strong phonon coupling through vacuum fluctuations, and observe the exchange of thermal energy between individual phonon modes. The experimental observation agrees well with our theoretical calculations and is unambiguously distinguished from other effects such as near-field radiation and electrostatic interaction. Our discovery of phonon transport through quantum fluctuations represents a previously unknown mechanism of heat transfer in addition to the conventional conduction, convection and radiation. It paves the way for the exploitation of quantum vacuum in energy transport at the nanoscale. Conventionally, heat transfer occurs by conduction, convection or radiation, but has also been theoretically predicted to occur through quantum fluctuations across a vacuum; this prediction has now been confirmed experimentally.

In a multi-fold universe, gravity emerges from Entanglement through the multi-fold mechanisms. As a result, gravity-like effects appear in between entangled particles that they be real or virtual. Long range, massless gravity results from entanglement of massless virtual particles. Entanglement of massive virtual particles leads to massive gravity contributions at very smalls scales. Multi-folds mechanisms also result into a spacetime that is discrete, with a random walk fractal structure and non-commutative geometry that is Lorentz invariant and where spacetime nodes and particles can be modeled with microscopic black holes. All these recover General Relativity at large scales and semi-classical model remain valid till smaller scales than usually expected. Gravity can therefore be added to the Standard Model resulting into what we define as SMG, the Standard Model with non-negligible gravity effects at its scales. This can contribute to resolving several open issues with the Standard Model without new Physics other than gravity. These considerations hints at a even stronger relationship between gravity and the Standard Model. Superstrings are encountered in the context of Multi-fold universes; but not as physical entities, or as entities encountered in the multi-fold universe spacetime. Their discovery in AdS(5) (+ extra dimensions) tangent to every multi-fold universe spacetime points are physically consistent with superstrings that would only exist in universes with negative cosmological constants. Yet, in previous papers, we did not analyze the details of the related string theory theorems and conjectures, about curvature and viable curvatures, and, in particular, we did not discuss criticisms made by some to the main incompatibility results. These are conjectures not accepted by all, or alternatives that seem to be able to avoid them. This paper provides an analysis that supports the proposal of the incompatibility of superstrings with positive curvature (asymptotic De Sitter), dark energy or cosmological constant. This result applies to superstring theories. But it is good to note that the reasoning is consistent with the multi-fold universe spacetime reconstruction model (random walks), inflation (including the approach based on Higgs field (minimally) coupled to gravity), and multi-fold dark energy mechanisms. It piles on the already asserted incompatibility of superstrings, and supersymmetry, with SMG based on asymptotic safety of gravity in multi-fold universes. In the context of multi-fold universes, it appears that the multi-fold universe spacetime emerges from the multi-fold random walk, while its dual tangent AdS(5), where the multi-folds, or gravitons, live, could be seen as emerging from superstrings. Superstrings are buffered by AdS(5) from (asymptotic) dS, and relieved from having to support its emergence or existence. The jury remains out on the exact physical relevance of superstrings beyond gravitons in AdS(5)., Latest at: https://shmaesphysics.wordpress.com/2021/01/12/the-string-swampland-and-de-sitter-vacua-a-consistent-perspective-for-superstrings-and-multi-fold-universes/ Related: https://shmaesphysics.wordpress.com/shmaes-physics-site-navigation/

International audience; ABSTRACTThis theoretical and preliminary work corresponds to the hope of extracting, without contradicting EMMY NOETHER's invariance theorem, an energy that is omnipresent, isotropic, uniform and present in the entire universe: that of the vacuum !This theoretical work shows that it should be possible to maintain over time a periodic vibration of a piezoelectric structure which generates current peaks during a fraction of the period of vibration. This is achieved by controlling automatically and at the opportune moments the perpetual and omnipresent action of Casimir attractive force between two electrodes, by an opposite and greater Coulomb force of at least a factor of two. This proportionality factor, Coulomb / Casimir Forces> = 2, is determined by the threshold voltage of enriched or depleted MOS transistors and defined during the manufacture of the device.The attractive Casimir force appearing between the two electrodes of a reflector deforms a piezoelectric bridge, which automatically induces the electric charges used by a Coulomb force on the return electrode. As long as the electric voltage, generated by the electric charges on one side of the piezoelectric bridge and connected to the gate of an enriched MOS transistor (MOSE) is below its threshold voltage, this transistor remains blocked. The electrical charges on the other side of the bridge are on the source of this transistor and remain confined to the moving electrode of the Casimir reflector. During this phase, the Coulomb return electrode is then grounded by closing the circuit consisting of series depleted MOS (MOSD). Likewise, the fixed electrode of the Casimir reflector is continuously grounded. The Coulomb force between the two electrodes of the Casimir reflector and between the piezoelectric bridge and the Coulomb return electrode is then zero. Depending on the deformation of the piezoelectric bridge, the electric charges present on the two electrodes of the piezoelectric bridge increase. They therefore increase on the gates of the enriched or depleted MOS and generate an electrical voltage greater than the threshold voltages of the MOSE and MOSD transistors. Thus, the circuit formed by MOSE in parallel closes and that formed by MOSD in series opens, then isolating the fixed return electrode from ground, which allows the charges present on the source to be distributed uniformly over this recall electrode. and be trapped there. Electric charges of opposite sign are then distributed over the two electrodes, one on one side of the piezoelectric bridge, the other on the return electrode! So , an attractive Coulomb force who can be greater than and in the opposite direction to that of Casimir then develops between these return electrodes. This attractive Coulomb force moves the two electrodes away of the Casimir reflector, reducing then cancelling the deformation of the bridge. It automatically disappears when the deformation of the piezoelectric bridge is cancelled out, letting the Casimir force again dominate and deform this bridge again for a new cycle! The device is found in the initial conditions which causes the structure to vibrate. When homogenizing the electrical charges on both sides of the return electrode, periodic current peaks appear for a fraction of the device's vibration time. These peaks of currents passing through an inductor spontaneously induce peaks of alternating voltages at the terminals of this device. Electronics without any power supply then transforms these weak alternating signals into a direct voltage of several volts. To manufacture these different structures, we are proposing an original technology making it possible to produce these electronics without power supply, as well as that of the control of the very weak interfaces between the electrodes of the Casimir reflector and that of the return electrodes of the vibrating structure!The Casimir and Coulomb forces, the current or voltage peaks appear spontaneously and without input of any external energy, likewise the transformation electronics have no power supply.The structure automatically enters vibration thus inducing current and voltage peaks converted into a usable direct voltage.Everything is only a consequence of the existence of the isotropic, homogeneous, and omnipresent Casimir force due to the quantum fluctuations of the vacuum.This set does not seem to contradict Emily Noether's theorem!"In the universe, everything is energy, everything is vibration, from the infinitely small to the infinitely large" Albert Einstein."A person who has never made mistakes has never tried to innovate." Albert Einstein

The holographic principle implies that quantum field theory (QFT) overcounts the number of independent degrees of freedom in quantum gravity. An argument due to Cohen, Kaplan, and Nelson (CKN) suggests that the number of degrees of freedom well described by QFT is even smaller than required by holographic bounds, and CKN interpreted this result as indicative of a correlation between the UV and IR cutoffs on QFT. Here, we consider an alternative interpretation in which the QFT degrees of freedom are depleted as a function of scale. We use a simple recipe to estimate the impact of depleted densities of states on precision observables, including the Lamb shift and lepton g−2. Although these observables are not sensitive to the level of depletion motivated by gravitational considerations, the phenomenological exercises also provide an interesting test of quantum field theory that is independent of underlying quantum gravity assumptions. A depleted density of states can also render the QFT vacuum energy UV insensitive, reconciling the success of QFT in describing ordinary particle physics processes and its apparent failure in predicting the cosmological constant.

A new technique in which atoms move slowly through a diffraction grating lets researchers measure the tiny Casimir-Polder interaction, a force that arises from quantum vacuum fluctuations.

We consider a quantum mechanical system to model the effect of quantum fields on the evolution of the early universe. The system consists of an inverted oscillator bilinearly coupled to a set of harmonic oscillators. We point out that the role of noise may be crucial in the dynamics of the oscillator, which is analyzed using the theory of harmonic oscillators with random frequency. Using this analogy we argue that, due to the fluctuations around its mean value, a positive vacuum energy density would not produce an exponentially expanding but an oscillating universe, in the same fashion that an inverted pendulum is stabilized by random oscillations of the suspension point (stochastic Kapitza pendulum). The results emphasize the relevance of noise in the evolution of the scale factor., 11 pages, no figures. Presentation improved. References added. Published in IJMPD

The two-loop correction to the mass of the ϕ4 kink is 0.0126λ/m in terms of the coupling λ and the meson mass m evaluated at the minimum of the potential. This is calculated using a recently proposed alternative to collective coordinates. Both the kink energy and the vacuum energy are IR divergent at this order. To cancel the divergence, the two energy densities are subtracted before integrating over space, or equivalently a finite counterterm is added to the Hamiltonian density to cancel the vacuum energy density. All spatial integrals are performed analytically. However in the last step of our calculation, integrals over virtual momenta are performed numerically.

Lattice results on sigma terms and global analysis of parton momentum fractions are used to give the quark and glue fractions of the proton mass and rest energy. The mass decomposition in terms of the trace of the energy-momentum tensor is renormalization group invariant. The decomposition of the rest energy from the Hamiltonian and the gravitational form factors are scheme and scale dependent. The separation of the energy-momentum tensor into the traceless part which is composed of the quark and glue parton momentum fractions and the trace part has the minimum scheme dependence. We identify the glue part of the trace anomaly $\langle H_{\beta}\rangle $ as the vacuum energy from the glue condensate in the vacuum. From the metric term of the gravitational form factors, which is the stress part of the stress-energy-momentum tensor, we find that the trace part of the rest energy, dominated by $\langle H_{\beta}\rangle$, gives a {\it constant} restoring pressure which balances that from the traceless part of the Hamiltonian to confine the hadron, much like the cosmological constant Einstein introduced for a static universe. From a lattice calculation of $\langle H_{\beta}\rangle$ in the charmonium, we deduce the associated string tension which turns out to be in good agreement with that from a Cornell potential which fits the charmonium spectrum., Comment: Version to be published in Phys. Rev. D

Masses of the three neutrino mass eigenstates are predicted to be m₀, 4m₀ & 22m₀ (or 23m₀) where m₀ = 2.283 (or 2.183) meV/c², based on two ad-hoc postulates. First postulate is that the mass m₀ of the lightest neutrino mass eigenstate is the smallest quantum of mass. The dimensionless gravitational coupling constant αg is then defined as, αg = m₀/Mp, where Mp is the Planck Mass. The second postulate is that the dark energy density of the ΛCDM model is ρΛ = αg⁴ ρp, where ρp is the Planck Density. Application of these postulates to neutrino oscillation data gives ΩΛ h² = 0.3354 (or 0.2807) in good agreement with the value obtained from cosmological data using ΛCDM model. The effective neutrino mass of the β decay is predicted to be mβ = 4.02m₀ (or 4.14m₀). We also predict the upper limits on the effective Majorana mass mββ of the neutrinoless double beta decay (0νββ). These upper limits are then used to calculate the lower limits on the half lifes of various isotopes expected to undergo 0νββ. Finally the two postulates are used to define a natural system of units.

Masses of the three neutrino mass eigenstates are predicted to be m0,4m0 & 22m0 where m0 = 2.283 meV/c². These predictions are arrived at by applying two ad-hoc postulates to neutrino oscillation data. First postulate is that the mass m0 of the lightest neutrino mass eigenstate is the smallest quantum of mass and masses of all the massive elementary particles are positive integral multiples of m0. The dimensionless gravitational coupling constant αg is then defined as, αg= m0/Mp, where Mp is the Planck Mass. The second postulate is that the dark energy is represented by a cosmological constant Λ or equivalently, a vacuum energy with constant density ρΛ= αg4ρp, where ρpis the Planck Density. These postulates are then used to predict the value of vacuum energy density to be ΩΛh2= 0.3354 which is in agreement with the ΛCDM model. Furthermore, the effective neutrino mass of the β decay is predicted to be mβ = 4.02m0. We also predict the effective Majorana mass of the neutrinoless double beta decay (0νββ) to be mββ ≤ 2.55m0. This upper bound on mββ is then used to calculate the lower bounds on the half-lifes of various isotopes expected to undergo 0νββ. Finally the two postulates are used to construct a natural system of units.

Within this publication, the Dirac equation is modified to take account of the electromagnetic field of sub-atomic particles, as well as their relativistic spatio-temporal spin states. This procedure therefore results in what turns out to be two asymmetric and different, positive and negative energies, rather than the equally sized identical quantities of opposite signs that Dirac obtained. The difference between each of these slightly different positive and negative energies thus ultimately yields a value that is very similar to that quoted for zero-point energy or dark energy, otherwise equally termed vacuum energy, and a final calculation for a predicted, outward-directed vacuum pressure of approximately \(- 0.6 \times 10^{{ - 8}}\) ergs/\({\text{cm}}^{2}\)—possibly explaining the expansion of the Universe—is also made. Finally, using this paper’s own theoretically calculated magnitude for a vacuum energy density of \(0.5963 \times 10^{{ - 8}}\) ergs/\({\text{cm}}^{3}\), it is shown that a possible value for the Hubble constant is \(71.55587\,{\text{km}}/({\text{s}}\,{\text{Mpc}})\).

In this research, the pseudo vacuum energy in the inflationary universe model, the Higgs field in the standard physical model and the dark energy in the observational cosmology are reduced to the positive energy system with strong negative pressure, and they are reduced to the repulsion (all the resistance to gravity). In the high-dimensional space-time, corresponding to the introduction of supergravity with the supersymmetry, we put forth the superrepulsion with the supersymmetry, and establish the arche-conjugate relationship between the supergravity and superrepulsion, so as to extend the holographic principle and the holographic dark energy model, and propose a new mechanism that can be promoted to the super holographic principle of high-dimensional universe. In the super-inflationary universe with rip-rebounding clusters which is studied here, the arche-conjugation is higher than the supersymmetry, so it becomes the core concept. From the basic component point of view, before or after the big bang, the gravitons and repulsons are coupled together, the negative energy contraction and the positive energy expansion work alternately, to form the arche-conjugate pulsator which is neither the point particle nor the linear superstring. In addition, we establish the path integral and its dynamic equation of quantum hedge unified field.

In this paper, we study quantum vacuum fluctuation effects on the mass density of a classical liquid arising from the conical topology of an effective idealized cosmic string spacetime, as well as from the mixed, Dirichlet, and Neumann boundary conditions in Minkowski spacetime. In this context, we consider a phonon field representing quantum excitations of the liquid density, which obeys an effective Klein-Gordon equation with the sound velocity replaced by the light velocity. In the idealized cosmic string spacetime, the phonon field is subject to a quasi-periodic condition. Moreover, in Minkowski spacetime, the Dirichlet and Neumann boundary conditions are applied on one and also two parallel planes. We, thus, in each case, obtain closed analytic expressions for the two-point function and the renormalized mean-squared density fluctuation of the liquid. We point out specific characteristics of the latter by plotting their graphs., Comment: 12 pages, 3 figures

It is shown that the Lambda component in the cosmological Lambda-CDM model can be conceived as vacuum energy, consisting of gravitational particles subject to Heisenberg’s energy-time uncertainty. These particles can be modelled as elementary polarisable Dirac-type dipoles (“darks”) in a fluidal space at thermodynamic equilibrium, with spins that are subject to the Bekenstein-Hawking entropy. Around the baryonic kernels, uniformly distributed in the universe, the spins are polarized, thereby invoking an increase of the effective gravitational strength of the kernels. It explains the dark matter effect of galaxies to the extent that a numerical value of Milgrom’s acceleration constant can be assigned by theory. Non-polarized vacuum particles beyond the baryonic kernels compose the dark energy at the cosmological level. The result is an interpretation of gravity at the quantum level in terms of quantitatively established shares in baryonic matter, dark matter and dark energy, which correspond with the values of the Lambda-CDM model.

Quantum effects in non-inertial frames and curved space-time have been studied for decades. One of the most intriguing discoveries is the existence of virtual particles in the quantum vacuum. One example in which such particles can be observed is through the Unruh effect, which predicts that a uniformly accelerated observer would see a thermal bath of (virtual) particles in the quantum vacuum. Initial doubts on the existence of these virtual particles were allayed by the Unruh De-Witt (UDW) detector, which promoted these virtual particles to real excitations of the detector. Ever since, semiclassical approaches to relativistic quantum field theory (QFT) in flat and curved space-time have been predominantly analysed through a two-level Unruh De-Witt detector utilizing perturbation theory. It is noted, however, that the change of relativistic frame preserves Gaussian properties (e.g. Gaussian distribution of the Wigner function) of the system. In this thesis, we specifically explore the effects of relativistic (non-inertial) reference frames on QFT by considering relativistic QFT in flat-space time. These systems are analysed from the perspective of Gaussian quantum information, via homodyne detection and UDW detectors with a harmonic oscillator degree of freedom.Our project starts by reviewing and developing bipartite/multi-partite entanglement measures (specifically, entanglement of formation), in the hope that we can utilize these measures to understand the entanglement properties of the quantum vacuum. In general, these measure have infinite degrees of freedom and are incomputable. In this project the multi-partite entanglement measure is applied to the Gaussian regime, which reduces the number of degrees of freedom to a finite one, hence making it a computable measure.In our next project, we attempt to understand how relativistic reference frames affect the communication between different observers. To obtain an intuition of its effect, a passive (time-delay) signal sent from a uniformly accelerated observer to a stationary observer was analysed. When we naively implemented the self-homodyne detection scheme, the signal appeared noisy. This effect was referred to as apparent decoherence, and its effect could be traced back to our naive assumption that all of the signal’s information would be stored in the time-delayed mode; the vacuum entanglement that pre-existed before the (time-delay) signal was created must be accounted for. We follow by analysing the effects that emerge due to communication between different relativistic reference frames. We then develop a communication technique referred to as ideal-homodyne which is a homodyne detection scheme robust to these effects. We used this detection scheme to analyse the correlation/entanglement properties of an accelerated signal (created via accelerated mirror, squeezer and phase shifter) sent to an inertial observer.In our last project, we utilize the knowledge that was gained through the prior projects to analyse (subcycle) electro-optic sampling. In the literature, there were doubts as to whether electro-optic sampling were truly detecting virtual particles in the quantum vacuum, or particle excitations that were created as a by-product of the detection mechanism. We were able to pin-point some similarities between electro-optic sampling and subcycle probe via the UDW detector. The regime in which the electro-optic sampling directly maps virtual particles from the vacuum into real excitations of the probe field was identified by establishing an equivalence to the UDW detector in certain parameter regimes.

A VPS is a special space probe able to travel using energy from vacuum. It can travel distances using vacuum around it as “fuel”.

In theories with extra dimensions, the cosmological hierarchy problem can be thought of as the unnaturally large radius of the observable universe in Kaluza-Klein units. We sketch a dynamical mechanism that relaxes this. In the early universe scenario we propose, three large spatial dimensions arise through tunneling from a 'cosmic egg', an effectively one-dimensional configuration with all spatial dimensions compact and of comparable, small size. If the string landscape is dominated by low-dimensional compactifications, cosmic eggs would be natural initial conditions for cosmology. A quantum cosmological treatment of a toy model egg predicts that, in a variant of the Hartle-Hawking state, cosmic eggs break to form higher dimensional universes with a small, but positive cosmological constant or quintessence energy. Hence cosmic egg cosmology yields a scenario in which the seemingly unnaturally small observed value of the vacuum energy can arise from natural initial conditions., 11 pages, 4 figures, 1 appendix

Using a holographic model, we study quantum field theories with a layer of one CFT surrounded by another CFT, on either a periodic or an infinite direction. We study the vacuum energy density in each CFT as a function of the central charges, the thickness of the layer(s), and the properties of the interfaces between the CFTs. The dual spacetimes in the holographic model include two regions separated by a dynamical interface with some tension. For two or more spatial dimensions, we find that a layer of CFT with more degrees of freedom than the surrounding one can have an anomalously large negative vacuum energy density for certain types of interfaces. The negative energy density (or null-energy density in the direction perpendicular to the interface) becomes arbitrarily large for fixed layer width when the tension of the bulk interface approaches a lower critical value. We argue that in cases where we have large negative energy density, we also have an anomalously high transition temperature to the high-temperature thermal state., 1+27 pages, 10 figures, minor comments added to discussion in this version

An optically levitated nonspherical particle in a vacuum is great for torque sensing and rotational quantum mechanics. Recently, we optically levitated silica nanodumbbells in a vacuum and drove them to rotate beyond 5 GHz. With an optically levitated nanorotor, we demonstrated a torque sensor with a record-high sensitivity [Nature Nanotechnology, 15, 89 (2020)]. Such an ultrasensitive torque sensor will have the potential to detect the long-sought quantum vacuum friction. We also demonstrated 5D cooling and observed nonlinear dynamics of an optically levitated nanodumbbell in a vacuum. This work is an important step towards full quantum control of the rigid-body motion of a levitated nonspherical particle.

In the present study, we mainly discuss the features of polytropic anti-de Sitter (PAdS) black hole solution, which can be taken into account also as a stable configuration for dark energy stars. A dark energy star is a hypothetical compact astrophysical object and it has gained astrophysical relevance in literature for several reasons, for instance, it may be another interpretation for observations of astronomical black hole candidates. The idea basically points out that falling matter is transformed into dark energy (or vacuum energy), as the matter falls through the event horizon. In the first step of our investigation, assuming thermodynamical parameters of the asymptotically AdS black hole are identical to those introduced for the generalized polytropic gas, we obtain an exact solution for the metric function describing interior domain of the PAdS black hole. Then, we investigate the physical features of intermediate (shell) region. Subsequently, we describe physical properties like energy conditions and hydrostatic equilibrium via mathematical calculations as well as graphical analyses. In the final step, because black holes can be naturally regarded as a thermal device, we focus on a heat engine process for the PAdS black hole and obtain an analytical expression for the efficiency in terms of entropy and temperature.