scholarly journals Prospects for Searching Thermal Effects, Non-Newtonian Gravity and Axion-Like Particles: Cannex Test of the Quantum Vacuum

Symmetry ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 407 ◽  
Author(s):  
Galina Klimchitskaya ◽  
Vladimir Mostepanenko ◽  
René Sedmik ◽  
Hartmut Abele
Keyword(s):  
Dark Matter ◽  
Thermal Effects ◽  
Coupling Constants ◽  
Newtonian Gravity ◽  
Quantum Vacuum ◽  
Parallel Plates ◽  
Interaction Range ◽  
Simultaneous Measurements ◽  
Order Of Magnitude ◽  
Type Interaction

We consider the Cannex (Casimir And Non-Newtonian force EXperiment) test of the quantum vacuum intended for measuring the gradient of the Casimir pressure between two flat parallel plates at large separations and constraining parameters of the chameleon model of dark energy in cosmology. A modification of the measurement scheme is proposed that allows simultaneous measurements of both the Casimir pressure and its gradient in one experiment. It is shown that with several improvements the Cannex test will be capable to strengthen the constraints on the parameters of the Yukawa-type interaction by up to an order of magnitude over a wide interaction range. The constraints on the coupling constants between nucleons and axion-like particles, which are considered as the most probable constituents of dark matter, could also be strengthened over a region of axion masses from 1 to 100 meV.

scholarly journals Dark Matter Axions, Non-Newtonian Gravity and Constraints on Them from Recent Measurements of the Casimir Force in the Micrometer Separation Range

Universe ◽  
2021 ◽  
Vol 7 (9) ◽  
pp. 343
Author(s):  
Galina L. Klimchitskaya ◽  
Vladimir M. Mostepanenko
Keyword(s):  
Dark Matter ◽  
Quantum Electrodynamics ◽  
Casimir Force ◽  
Interaction Strength ◽  
Newtonian Gravity ◽  
Yukawa Interaction ◽  
Coupling Constant ◽  
Differential Measurement ◽  
Type Interaction ◽  
Coated Surfaces

We consider axionlike particles as the most probable constituents of dark matter, the Yukawa-type corrections to Newton’s gravitational law and constraints on their parameters following from astrophysics and different laboratory experiments. After a brief discussion of the results by Prof. Yu. N. Gnedin in this field, we turn our attention to the recent experiment on measuring the differential Casimir force between Au-coated surfaces of a sphere and the top and bottom of rectangular trenches. In this experiment, the Casimir force was measured over an unusually wide separation region from 0.2 to 8μm and compared with the exact theory based on first principles of quantum electrodynamics at nonzero temperature. We use the measure of agreement between experiment and theory to obtain the constraints on the coupling constant of axionlike particles to nucleons and on the interaction strength of a Yukawa-type interaction. The constraints obtained on the axion-to-nucleon coupling constant and on the strength of a Yukawa interaction are stronger by factors of 4 and 24, respectively, than those found previously from gravitational experiments and measurements of the Casimir force but weaker than the constraints following from a differential measurement where the Casimir force was nullified. Some other already performed and planned experiments aimed at searching for axions and non-Newtonian gravity are discussed, and their prospects are evaluated.

scholarly journals CASIMIR EFFECT AS A TEST FOR THERMAL CORRECTIONS AND HYPOTHETICAL LONG-RANGE INTERACTIONS

2005 ◽  
Vol 20 (11) ◽  
pp. 2205-2221 ◽  
Author(s):  
G. L. KLIMCHITSKAYA ◽  
R. S. DECCA ◽  
E. FISCHBACH ◽  
D. E. KRAUSE ◽  
D. LÓPEZ ◽  
...  
Keyword(s):  
Long Range ◽  
Casimir Force ◽  
Casimir Effect ◽  
Newtonian Gravity ◽  
Parallel Plates ◽  
Interaction Range ◽  
Rigorous Approach ◽  
Long Range Interactions ◽  
The Standard Model

We have performed a precise experimental determination of the Casimir pressure between two gold-coated parallel plates by means of a micromachined oscillator. In contrast to all previous experiments on the Casimir effect, where a small relative error (varying from 1% to 15%) was achieved only at the shortest separation, our smallest experimental error (~ 0.5%) is achieved over a wide separation range from 170 nm to 300 nm at 95% confidence. We have formulated a rigorous metrological procedure for the comparison of experiment and theory without resorting to the previously used root-mean-square deviation, which has been criticized in the literature. This enables us to discriminate among different competing theories of the thermal Casimir force, and to resolve a thermodynamic puzzle arising from the application of Lifshitz theory to real metals. Our results lead to a more rigorous approach for obtaining constraints on hypothetical long-range interactions predicted by extra-dimensional physics and other extensions of the Standard Model. In particular, the constraints on non-Newtonian gravity are strengthened by up to a factor of 20 in a wide interaction range at 95% confidence.

scholarly journals Direct limits for scalar field dark matter from a gravitational-wave detector

2021 ◽  
Author(s):  
Hartmut Grote ◽  
Sander Vermeulen ◽  
Philip Relton ◽  
Vivien Raymond ◽  
Christoph Affeldt ◽  
...  
Keyword(s):  
Dark Matter ◽  
Scalar Field ◽  
Gravitational Wave ◽  
Coupling Constants ◽  
Gravitational Wave Detector ◽  
Optical Cavities ◽  
Wave Detector ◽  
Direct Limits ◽  
Order Of Magnitude ◽  
Noise Limit

Abstract The nature of dark matter remains unknown to date and several candidate particles are being considered in a dynamically changing research landscape [1]. Scalar field dark matter is a prominent option that is being explored with precision instruments such as atomic clocks and optical cavities [2-8]. Here we report on the first direct search for scalar field dark matter utilising a gravitational-wave detector operating beyond the quantum shot-noise limit. We set new upper limits for the coupling constants of scalar field dark matter as a function of its mass by excluding the presence of signals that would be produced through the direct coupling of this dark matter to the beamsplitter of the GEO600 interferometer. The new constraints improve upon bounds from previous direct searches by more than six orders of magnitude and are more stringent than limits obtained in tests of the equivalence principle by one order of magnitude. Our work demonstrates that scalar field dark matter can be probed or constrained with direct searches using gravitational-wave detectors and highlights the potential of quantum-enhanced interferometry for dark matter detection.

scholarly journals On N-body simulations of globular cluster streams

2021 ◽  
Vol 504 (1) ◽  
pp. 648-653
Author(s):  
Nilanjan Banik ◽  
Jo Bovy
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Analytical Models ◽  
Numerical Density ◽  
Stellar Streams ◽  
Small Scales ◽  
Order Of Magnitude ◽  
Low Mass ◽  
Stream Density ◽  
Tidal Streams

ABSTRACT Stellar tidal streams are sensitive tracers of the properties of the gravitational potential in which they orbit and detailed observations of their density structure can be used to place stringent constraints on fluctuations in the potential caused by, e.g. the expected populations of dark matter subhaloes in the standard cold dark matter (CDM) paradigm. Simulations of the evolution of stellar streams in live N-body haloes without low-mass dark matter subhaloes, however, indicate that streams exhibit significant perturbations on small scales even in the absence of substructure. Here, we demonstrate, using high-resolution N-body simulations combined with sophisticated semi-analytical and simple analytical models, that the mass resolutions of 104–$10^5\, \rm {M}_{\odot }$ commonly used to perform such simulations cause spurious stream density variations with a similar magnitude on large scales as those expected from a CDM-like subhalo population and an order of magnitude larger on small, yet observable, scales. We estimate that mass resolutions of ${\approx}100\, \rm {M}_{\odot }$ (${\approx}1\, \rm {M}_{\odot }$) are necessary for spurious, numerical density variations to be well below the CDM subhalo expectation on large (small) scales. That streams are sensitive to a simulation’s particle mass down to such small masses indicates that streams are sensitive to dark matter clustering down to these low masses if a significant fraction of the dark matter is clustered or concentrated in this way, for example, in MACHO models with masses of 10–$100\, \rm {M}_{\odot }$.

scholarly journals Gravitational polarization of the quantum vacuum caused by two point-like bodies

2021 ◽  
Vol 503 (4) ◽  
pp. 5091-5099
Author(s):  
Dragan Slavkov Hajdukovic ◽  
Sergej Walter
Keyword(s):  
Dark Matter ◽  
Solar System ◽  
Charge Density ◽  
Numerical Method ◽  
Quantum Vacuum ◽  
Body System ◽  
Complex Fluid ◽  
The Impact ◽  
The Universe ◽  
Gravitational Charge

ABSTRACT In a recent paper, quantum vacuum was considered as a source of gravity, and the simplest, phenomenon, the gravitational polarization of the quantum vacuum by an immersed point-like body, was studied. In this paper, we have derived the effective gravitational charge density of the quantum vacuum, caused by two immersed point-like bodies. Among others, the obtained result proves that quantum vacuum can have regions with a negative effective gravitational charge density. Hence, quantum vacuum, the ‘ocean’ in which all matter of the Universe is immersed, acts as a complex fluid with a very variable gravitational charge density that might include both positive and negative densities; a crucial prediction that can be tested within the Solar system. In the general case of ${N \ge {\rm{3}}}$ point-like bodies, immersed in the quantum vacuum, the analytical solutions are not possible, and the use of numerical methods is inevitable. The key point is that an appropriate numerical method, for the calculation of the effective gravitational charge density of the quantum vacuum induced by N immersed bodies, might be crucial in description of galaxies, without the involvement of dark matter or a modification of gravity. The development of such a valuable numerical method, is not possible, without a previous (and in this study achieved) understanding of the impact of a two-body system.

scholarly journals Thermal Casimir effect with general boundary conditions

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
J. M. Muñoz-Castañeda ◽  
L. Santamaría-Sanz ◽  
M. Donaire ◽  
M. Tello-Fraile
Keyword(s):  
Boundary Conditions ◽  
Vacuum Energy ◽  
Casimir Effect ◽  
Quantum Field ◽  
Quantum Vacuum ◽  
Parallel Plates ◽  
Casimir Forces ◽  
Thermal Correction ◽  
Frequency Independent ◽  
Scalar Quantum

Abstract In this paper we study the system of a scalar quantum field confined between two plane, isotropic, and homogeneous parallel plates at thermal equilibrium. We represent the plates by the most general lossless and frequency-independent boundary conditions that satisfy the conditions of isotropy and homogeneity and are compatible with the unitarity of the quantum field theory. Under these conditions we compute the thermal correction to the quantum vacuum energy as a function of the temperature and the parameters encoding the boundary condition. The latter enables us to obtain similar results for the pressure between plates and the quantum thermal correction to the entropy. We find out that our system is thermodynamically stable for any boundary conditions, and we identify a critical temperature below which certain boundary conditions yield attractive, repulsive, and null Casimir forces.

scholarly journals MODIFIED GRAVITY AS A COMMON CAUSE FOR COSMIC ACCELERATION AND FLAT GALAXY ROTATION CURVES

2012 ◽  
Vol 21 (11) ◽  
pp. 1242002 ◽  
Author(s):  
PRITI MISHRA ◽  
TEJINDER P. SINGH
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Cosmic Acceleration ◽  
Accelerating Universe ◽  
Rotation Curves ◽  
Common Cause ◽  
Order Of Magnitude ◽  
Flat Rotation Curves ◽  
Acceleration Of The Universe ◽  
Galaxy Rotation Curves

Flat galaxy rotation curves and the accelerating Universe both imply the existence of a critical acceleration, which is of the same order of magnitude in both the cases, in spite of the galactic and cosmic length scales being vastly different. Yet, it is customary to explain galactic acceleration by invoking gravitationally bound dark matter, and cosmic acceleration by invoking a "repulsive" dark energy. Instead, might it not be the case that the flatness of rotation curves and the acceleration of the Universe have a common cause? In this essay we propose a modified theory of gravity. By applying the theory on galactic scales we demonstrate flat rotation curves without dark matter, and by applying it on cosmological scales we demonstrate cosmic acceleration without dark energy.

Numerical Prediction of Flow and Heat Transfer in a Parallel Plate Channel With Staggered Fins

1987 ◽  
Vol 109 (1) ◽  
pp. 25-30 ◽  
Author(s):  
K. M. Kelkar ◽  
S. V. Patankar
Keyword(s):  
Heat Transfer ◽  
Local Heat Transfer ◽  
Periodic Variation ◽  
Local Heat ◽  
Temperature Fields ◽  
Parallel Plates ◽  
Constant Property ◽  
Cross Sectional ◽  
Flow And Heat Transfer ◽  
Order Of Magnitude

Fluid flow and heat transfer in two-dimensional finned passages were analyzed for constant property laminar flow. The passage is formed by two parallel plates to which fins are attached in a staggered fashion. Both the plates are maintained at a constant temperature. Streamwise periodic variation of the cross-sectional area causes the flow and temperature fields to repeat periodically after a certain developing length. Computations were performed for different values of the Reynolds number, the Prandtl number, geometric parameters, and the fin-conductance parameter. The fins were found to cause the flow to deflect significantly and impinge upon the opposite wall so as to increase the heat transfer significantly. However, the associated increase in pressure drop was an order of magnitude higher than the increase in heat transfer. Streamline patterns and local heat transfer results are presented in addition to the overall results.

scholarly journals Quantitative Support for Borowski’s Theory of Gravitation

2013 ◽  
Vol 17 ◽  
pp. 67-71 ◽  
Author(s):  
Michael A. Persinger
Keyword(s):  
Dark Matter ◽  
Gravitational Constant ◽  
Planetary Motion ◽  
Free Oscillations ◽  
Energy Equivalence ◽  
Order Of Magnitude ◽  
Theory Of Gravitation

The Borowski Theory of Gravitation (BTG) indicates that movements of mass such as planets through space are determined by differential pressures from dark matter. One of the consequences of the final epoch is that there would be no matter but only distance. Quantitative solutions indicate that the tensor to set universal average dark matter pressure equal to G, the gravitational constant, would require that the terminal length would be ~2.2∙1069 m or effectively identical to current estimates of energy equivalence of the universal mass. For the earth’s orbit the force from the dark pressure is the same order of magnitude as the force associated with the product of the planet’s mass and background free oscillations whose origins are still ambiguous. The convergences of solutions suggest that the BTG may reveal alternative interpretations and mechanisms for the role of gravitation in planetary motion.

scholarly journals Brownian motion and polarized three-dimensional quantum vacuum

2021 ◽  
Vol 67 (4 Jul-Aug) ◽  
Author(s):  
Davide Fiscaletti
Keyword(s):  
Dark Matter ◽  
Brownian Motion ◽  
Energy Density ◽  
Nonlinear Model ◽  
Vacuum Energy ◽  
Three Dimensional ◽  
Vacuum Energy Density ◽  
Quantum Vacuum ◽  
Virtual Particles ◽  
Fundamental Entity

A nonlinear model of Brownian motion is developed in a three-dimensional quantum vacuum defined by a variable quantum vacuum energy density corresponding to processes of creation/annihilation of virtual particles. In this model, the polarization of the quantum vacuum determined by a perturbative fluctuation of the quantum vacuum energy density associated with a fluctuating viscosity, which mimics the action of dark matter, emerges as the fundamental entity which generates the Brownian motion.

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