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

Abstract

PreprintVersionWe 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.collaboration. On the background of Casimir forces, one could also search for axions and other axion-like particles [13][14][15][16][17][18][19][20] which are considered as hypothetical constituents of dark matter. It is remarkable that taken together, dark energy and dark matter contribute for more than 95% of the energy of the Universe, leaving less than 5% to the forms of energy we are presently capable to observe directly [6].Precise measurements of the Casimir force revealed a problem that the experimental data agree with theoretical predictions of the fundamental Lifshitz theory only under the condition that in calculations one disregards the relaxation properties of conduction electrons and the conductivity at a constant current for metallic and dielectric boundary surfaces, respectively (see review in [5,21] and more modern experiments [22][23][24][25][26][27]). Theoretically, it was shown that an inclusion of the relaxation properties of conduction electrons and the conductivity at a constant current in computations results in a violation of the Nernst heat theorem for the Casimir entropy (see review in [5,21] and further results [28][29][30][31]). Taking into account that both the relaxation properties of conduction electrons for metals and the conductivity at a constant current for dielectrics are well studied really existing phenomena, there must be profound physical reasons for disregarding them in calculations of the Casimir force caused by the zero-point and thermal fluctuations of the electromagnetic field.All precise experiments on measuring the Casimir interaction mentioned above have been performed in the sphere-plate geometry at surface separations below a micrometer. In this paper, we consider the Cannex (Casimir And Non-Newtonian force EXperiment) that was designed to test the quantum vacuum in the configuration of two parallel plates at separations up to 15 µm [32,33]. In addition to the already discussed possibility of testing the nature of dark energy [32], we consider here the potentialities of this experiment for searching thermal effects in the Casimir force, stronger constraints on Yukawa-type c...

Nonequilibrium effects in the Casimir force between two similar metallic plates kept at different temperatures

“…These effects could be observed using the experimental setup described in Refs. [43,52], where the upper plate plays the role of a sensor suspended by the springs and the lower plate is mounted on a piezo-electric stage. Taking into account that an immediate application of the above computational results requires the vacuum conditions outside of both plates, their thickness should be chosen sufficiently large (typically more than 0.5 µm) in order that a material underlying the lower plate will not impact on the nonequilibrium pressure.…”

Casimir pressure between metallic plates out of thermal equilibrium: Proposed test for the relaxation properties of free electrons

“…In addition to the recent proposal [50], we now present another modification of the CAN-NEX setup, allowing to increase the temperature of the lower plate by 10 K with no loss in the sensitivity. In fact, the improved sensitivities mentioned above require a temperature stability of the sensor better than 1 mK.…”

“…In this paper, we propose another experimental possibility to discriminate between two different theoretical approaches in the nonequilibrium Casimir force using a modified setup of the CANNEX test of the quantum vacuum (Casimir And Non-Newtonian force EXperiment) [48][49][50]. We calculate the nonequilibrium Casimir pressure in the configuration of two parallel plates, each of which consists of a sufficiently thick Au layer deposited on a dielectric substrate.…”

Precision measurements of the gradient of the Casimir force between ultraclean metallic surfaces at larger separations

“…This made harder the theoretical solution to the problem and called for precise measurements of the Casimir interaction in the micrometer separation range. Several experiments of this kind directed to the resolution of the Casimir puzzle and Casimir conundrum have been proposed recently[79][80][81][82][83].The main improvements made in the experiment presented here are the use of much softer cantilever, which allowed the increase of the calibration constant by up to an order of magnitude, and implementation of the two-step cleaning procedure by means of the UV light and Ar ions, which resulted in ultra clean surfaces of both the internal walls of vacuum chamber and of the test bodies at ultrahigh (< 5 × 10 −9 Torr ≈ 0.7 × 10 −6 Pa) and stable vacuum. This allowed to reach low (a few mV) and stable residual potential difference which was independent of separation for the regular (not specially selected) samples.…”