Search

Novel interactions beyond the four known fundamental forces in nature (electromagnetic, gravitational, strong and weak interactions), may arise due to "new physics" beyond the standard model, manifesting as a "fifth force". This review is focused on spin-dependent fifth forces mediated by exotic bosons such as spin-0 axions and axionlike particles and spin-1 Z' bosons, dark photons, or paraphotons. Many of these exotic bosons are candidates to explain the nature of dark matter and dark energy, and their interactions may violate fundamental symmetries. Spin-dependent interactions between fermions mediated by the exchange of exotic bosons have been investigated in a variety of experiments, particularly at the low-energy frontier. Experimental methods and tools used to search for exotic spin-dependent interactions, such as atomic comagnetometers, torsion balances, nitrogen-vacancy spin sensors, and precision atomic and molecular spectroscopy, are described. A complete set of interaction potentials, derived based on quantum field theory with minimal assumptions and characterized in terms of reduced coupling constants, are presented. A comprehensive summary of existing experimental and observational constraints on exotic spin-dependent interactions is given, illustrating the current research landscape and promising directions of further research., Comment: 100 pages, 16 figures, Invited review submitted to Reviews of Modern Physics (RMP)

High-intensity neutron beams, such as those available at the European Spallation Source (ESS), provide new opportunities for fundamental discoveries. Here we discuss a novel Ramsey neutron-beam experiment to search for ultralight axion dark matter through its coupling to neutron spins, which would cause the neutron spins to rotate about the velocity of the neutrons relative to the dark matter halo. We estimate that experiments at the HIBEAM beamline at the ESS can improve the sensitivity to the axion-neutron coupling compared to the current best laboratory limits by up to $2-3$ orders of magnitude over the axion mass range $10^{-22} \, \textrm{eV} - 10^{-16}$ eV., Comment: 8 pages, 3 figures

An effect of alloying of the monoclinic beta- Ga2O3 with Al2O3 and In2O3 on the photoluminescent, thermoluminescent and persistent luminescent properties of Cr3+ ions has been comprehensively investigated. For this purpose, various series of Cr3+ and Ca2+ co-doped microcrystalline phosphors were synthesized by the solution combustion method, including pseudobinary compounds like (Ga-Al)2O3 with up to 20% Al and (Ga-In)2O3 with up to 50% In as well as pseudoternary compounds (Ga Al In)2O3 with balanced proportion of Al, Ga and In. The phase composition and crystal structure of the obtained materials were examined by X-ray powder diffraction technique. Detailed luminescence studies were conducted for the (Ga-Al)2O3 and (Ga-In)2O3 compounds which exhibited a single-phase monoclinic structure. Low-temperature and time-resolved photoluminescence investigations of the Cr-doped pseudobinary compounds unveiled several types of Cr3+ centres, attributed to the Al-, Ga- and In-centred octahedra in the studied alloys. The obtained results underscore the benefit of bandgap engineering through alteration in the host lattice chemical composition for efficient tuning of the thermoluminescent and persistent luminescent properties of the near-infrared-emitting beta Ga2O3:Cr based phosphors. Furthermore, it was demonstrated that modification of the chemical composition of the host lattice also adjusts the thermometric performance of the studied phosphors. Indeed, the specific sensitivity of the beta- Ga2O3:Cr3+ decay time luminescence thermometer showed nearly twofold enhancement when the host lattice was alloyed with 30% of In2O3., Comment: 35 pages, 14 figures

Background and Aim of Study: The mental health and social adaptation of young students and cadets in wartime conditions is a new and understudied problem. The aim of the study: to identify the particularities of psychological well-being and social adaptation of students and cadets in wartime conditions. Materials and Methods: Our study was conducted among the students and cadets of two Ukrainian universities (KNUIA, UzhNU) in 2023, February. 327 participants were divided into 3 groups: 1) 112 cadets whose permanent disposition was changed in Ukraine; 2) 108 students who were displaced and who are in Ukraine and EU countries; 3) 107 students who did not change their place of permanent residence and who are in Ukraine in the combat zone or near it. The 28-item General Health Questionnaire (GHQ-28) to assess psychological well-being and emotional stability, and the Social Support Questionnaire (F-SozU K-22) to determine the particularities of emotional support, practical support, and social integration were used in the study. Appropriate internal consistency values (Cronbach a between 0.817 and 0.903) were found for both scales. Results: Group 1 has the best general health indicator: 1.65 times better than Group 3. The levels of somatic symptoms, anxiety and insomnia are lower in Group 1 (practically the same in women and men), and higher in Group 3. The highest rates of social dysfunction are found in Group 3. Men in all groups have more pronounced social dysfunction; women in all groups have more pronounced severe depression. Group 1 total perceived social support is 1.89 times better than Group 3. Emotional support, social integration are highest in Group 1, practical support is highest in Group 2. Conclusions: The lowest levels of psychological well-being and social adaptation were found in Group 3. This is probably due to uncertainty about the future, constant instability and insecurity. Teachers and psychologists are urged to consider the identified psychological and social peculiarities in the educational and clinical process when dealing with young students.

With the construction of the European Spallation Source, a remarkable opportunity has emerged to conduct high sensitivity searches for neutron oscillations, including a first search for thirty years for free neutrons converting to antineutrons. Furthermore, searches can be made for transitions of neutrons and antineutrons to sterile neutron states. Upgrades to the ESS infrastructure allow an improved HIBEAM design that would provide an increase in sensitivity by an order of magnitude compared to previous work. The HIBEAM program focuses on processes that violate baryon number by one or two units. The observation of a process satisfying one of the Sakharov conditions addresses the open question of the origin of the matter-antimatter asymmetry in the Universe. Sterile neutron states would belong to a `dark' sector of particles which may explain dark matter. As electrically neutral, meta-stable objects that can be copiously produced and studied, neutrons represent an attractive portal to a `dark' sector. The HIBEAM instrument can also be utilised for other purposes such as direct searches for ultralight axion dark matter. This paper describes the capability, design, infrastructure, and potential of the HIBEAM program. This includes a dedicated beamline, neutron optical system, magnetic shielding and control, and detectors for neutrons and antineutrons., Comment: 58 pages, 23 figures

Particle physics today faces the challenge of explaining the mystery of dark matter, the origin of matter over anti-matter in the Universe, the origin of the neutrino masses, the apparent fine-tuning of the electro-weak scale, and many other aspects of fundamental physics. Perhaps the most striking frontier to emerge in the search for answers involves new physics at mass scales comparable to familiar matter, below the GeV-scale, or even radically below, down to sub-eV scales, and with very feeble interaction strength. New theoretical ideas to address dark matter and other fundamental questions predict such feebly interacting particles (FIPs) at these scales, and indeed, existing data provide numerous hints for such possibility. A vibrant experimental program to discover such physics is under way, guided by a systematic theoretical approach firmly grounded on the underlying principles of the Standard Model. This document represents the report of the FIPs 2022 workshop, held at CERN between the 17 and 21 October 2022 and aims to give an overview of these efforts, their motivations, and the decadal goals that animate the community involved in the search for FIPs., Comment: 383 pp, 176 figures

Numerous observations suggest that there exist undiscovered beyond-the-Standard-Model particles and fields. Because of their unknown nature, these exotic particles and fields could interact with Standard Model particles in many different ways and assume a variety of possible configurations. Here we present an overview of the Global Network of Optical Magnetometers for Exotic physics searches (GNOME), our ongoing experimental program designed to test a wide range of exotic physics scenarios. The GNOME experiment utilizes a worldwide network of shielded atomic magnetometers (and, more recently, comagnetometers) to search for spatially and temporally correlated signals due to torques on atomic spins from exotic fields of astrophysical origin. We survey the temporal characteristics of a variety of possible signals currently under investigation such as those from topological defect dark matter (axion-like particle domain walls), axion-like particle stars, solitons of complex-valued scalar fields (Q-balls), stochastic fluctuations of bosonic dark matter fields, a solar axion-like particle halo, and bursts of ultralight bosonic fields produced by cataclysmic astrophysical events such as binary black hole mergers., Comment: 22 pages, 12 figures, submitted to Annalen der Physik

Ultra-low-mass axions are a viable dark matter candidate and may form a coherently oscillating classical field. Nuclear spins in experiments on Earth might couple to this oscillating axion dark-matter field, when propagating on Earth's trajectory through our Galaxy. This spin coupling resembles an oscillating pseudo-magnetic field which modulates the spin precession of nuclear spins. Here we report on the null result of a demonstration experiment searching for a frequency modulation of the free spin-precession signal of \magHg in a \SI{1}{\micro\tesla} magnetic field. Our search covers the axion mass range $10^{-16}~\textrm{eV} \lesssim m_a \lesssim 10^{-13}~\textrm{eV}$ and achieves a peak sensitivity to the axion-nucleon coupling of $g_{aNN} \approx 3.5 \times 10^{-6}~\textrm{GeV}^{-1}$., Comment: 18 pages, 4 images, submitted to SciPost Physics

The study analyzes the impact of constant and alternating magnetic fields and alternating electric fields on various growth parameters of soy plants: the germination energy and capacity, plants emergence and number, the Yield(II) of the fresh mass of seedlings, protein content, and photosynthetic parameters. Four cultivars were used: MAVKA, MERLIN, VIOLETTA, and ANUSZKA. Moreover, the advanced Machine Learning processing pipeline was proposed to distinguish the impact of physical factors on photosynthetic parameters. It is possible to distinguish exposition on different physical factors for the first three cultivars; therefore, it indicates that the EM factors have some observable effect on soy plants. Moreover, some influence of physical factors on growth parameters was observed. The use of ELM (Electromagnetic) fields had a positive impact on the germination rate in Merlin plants. The highest values were recorded for the constant magnetic field (CMF) - Merlin, and the lowest for the alternating electric field (AEF) - Violetta. An increase in terms of emergence and number of plants after seed stimulation was observed for the Mavka cultivar, except for the AEF treatment (number of plants after 30 days) (...)

Differential privacy (DP) data synthesizers support public release of sensitive information, offering theoretical guarantees for privacy but limited evidence of utility in practical settings. Utility is typically measured as the error on representative proxy tasks, such as descriptive statistics, accuracy of trained classifiers, or performance over a query workload. The ability for these results to generalize to practitioners' experience has been questioned in a number of settings, including the U.S. Census. In this paper, we propose an evaluation methodology for synthetic data that avoids assumptions about the representativeness of proxy tasks, instead measuring the likelihood that published conclusions would change had the authors used synthetic data, a condition we call epistemic parity. Our methodology consists of reproducing empirical conclusions of peer-reviewed papers on real, publicly available data, then re-running these experiments a second time on DP synthetic data, and comparing the results. We instantiate our methodology over a benchmark of recent peer-reviewed papers that analyze public datasets in the ICPSR repository. We model quantitative claims computationally to automate the experimental workflow, and model qualitative claims by reproducing visualizations and comparing the results manually. We then generate DP synthetic datasets using multiple state-of-the-art mechanisms, and estimate the likelihood that these conclusions will hold. We find that state-of-the-art DP synthesizers are able to achieve high epistemic parity for several papers in our benchmark. However, some papers, and particularly some specific findings, are difficult to reproduce for any of the synthesizers. We advocate for a new class of mechanisms that favor stronger utility guarantees and offer privacy protection with a focus on application-specific threat models and risk-assessment., Comment: Preprint. 14 pages

Ultralight scalar dark matter may induce apparent oscillations of the muon mass, which may be directly probed via temporal shifts in the spectra of muonium and muonic atoms. Existing datasets and ongoing spectroscopy measurements with muonium are capable of probing scalar-muon interactions that are up to 12 orders of magnitude more stringent than astrophysical bounds. Ongoing free-fall experiments with muonium can probe forces associated with the exchange of virtual ultralight scalar bosons between muons and standard-model particles, offering up to 5 orders of magnitude improvement in sensitivity over complementary laboratory and astrophysical bounds., Comment: 14 pages, 2 figures, version accepted for publication in PRL

We present a concept for a high-precision optical atomic clock (OAC) operating on an Earth-orbiting space station. This pathfinder science mission will compare the space-based OAC with one or more ultra-stable terrestrial OACs to search for space-time-dependent signatures of dark scalar fields that manifest as anomalies in the relative frequencies of station-based and ground-based clocks. This opens the possibility of probing models of new physics that are inaccessible to purely ground-based OAC experiments where a dark scalar field may potentially be strongly screened near Earth's surface. This unique enhancement of sensitivity to potential dark matter candidates harnesses the potential of space-based OACs., Comment: Submitted to Quantum Sci. Technol. special issue: Cold atom in space

Axions are well-motivated dark matter candidates with simple cosmological production mechanisms. They were originally introduced to solve the strong CP problem, but also arise in a wide range of extensions to the Standard Model. This Snowmass white paper summarizes axion phenomenology and outlines next-generation laboratory experiments proposed to detect axion dark matter. There are vibrant synergies with astrophysical searches and advances in instrumentation including quantum-enabled readout, high-Q resonators and cavities and large high-field magnets. This white paper outlines a clear roadmap to discovery, and shows that the US is well-positioned to be at the forefront of the search for axion dark matter in the coming decade., Comment: restore and expand author list

The last decade has seen unprecedented effort in dark matter model building at all mass scales coupled with the design of numerous new detection strategies. Transformative advances in quantum technologies have led to a plethora of new high-precision quantum sensors and dark matter detection strategies for ultralight ($<10\,$eV) bosonic dark matter that can be described by an oscillating classical, largely coherent field. This white paper focuses on searches for wavelike scalar and vector dark matter candidates., Comment: Snowmass 2021 White Paper

Ultralight bosonic dark matter (UBDM) can be described by a classical wave-like field oscillating near the Compton frequency of the bosons. If a measurement scheme for the direct detection of UBDM interactions is sensitive to a signature quadratic in the field, then there is a near-zero-frequency (dc) component of the signal. Thus, a detector with a given finite bandwidth can be used to search for bosons with Compton frequencies many orders of magnitude larger than its bandwidth. This opens the possibility of a detection scheme analogous to Hanbury Brown and Twiss intensity interferometry. Assuming that the UBDM is virialized in the galactic gravitational potential, the random velocities produce slight deviations from the Compton frequency. These result in stochastic fluctuations of the intensity on a time scale determined by the spread in kinetic energies. In order to mitigate ubiquitous local low-frequency noise, a network of sensors can be used to search for the stochastic intensity fluctuations by measuring cross-correlation between the sensors. This method is inherently broadband, since a large range of Compton frequencies will yield near-zero-frequency components within the sensor bandwidth that can be searched for simultaneously. Measurements with existing sensor networks have sufficient sensitivity to search experimentally unexplored parameter space., Comment: 11 pages, 4 figures. Supplementary material included after the references

We summarize the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportunities offered by their deployment in space, and the developments needed before cold atoms could be operated in space. The cold atom technologies discussed include atomic clocks, quantum gravimeters and accelerometers, and atom interferometers. Prospective applications include metrology, geodesy and measurement of terrestrial mass change due to, e.g., climate change, and fundamental science experiments such as tests of the equivalence principle, searches for dark matter, measurements of gravitational waves and tests of quantum mechanics. We review the current status of cold atom technologies and outline the requirements for their space qualification, including the development paths and the corresponding technical milestones, and identifying possible pathfinder missions to pave the way for missions to exploit the full potential of cold atoms in space. Finally, we present a first draft of a possible road-map for achieving these goals, that we propose for discussion by the interested cold atom, Earth Observation, fundamental physics and other prospective scientific user communities, together with ESA and national space and research funding agencies., Comment: Summary of the Community Workshop on Cold Atoms in Space and corresponding Road-map: https://indico.cern.ch/event/1064855/

The detection of variations of fundamental constants of the Standard Model would provide us with compelling evidence of new physics, and could lift the veil on the nature of dark matter and dark energy. In this work, we discuss how a network of atomic and molecular clocks can be used to look for such variations with unprecedented sensitivity over a wide range of time scales. This is precisely the goal of the recently launched QSNET project: A network of clocks for measuring the stability of fundamental constants. QSNET will include state-of-the-art atomic clocks, but will also develop next-generation molecular and highly charged ion clocks with enhanced sensitivity to variations of fundamental constants. We describe the technological and scientific aims of QSNET and evaluate its expected performance. We show that in the range of parameters probed by QSNET, either we will discover new physics, or we will impose new constraints on violations of fundamental symmetries and a range of theories beyond the Standard Model, including dark matter and dark energy models.

We study the scattering of surface TM-polarized plasmon-polariton waves (PPWs) by the finite red region of plane metal-vacuum boundary with randomly inhomogeneous impedance. We analyze the solution of the integral equation connecting the scattered field with the field of the oncoming PPWs, that is valid for any strength of the scattering and dissipative properties of the conducting half-space. As a measure of scattering strength, the Hilbert norm of the intermode scattering operator is used. It is shown that the intensity of the scattering is not only determined by the parameters of the random impedance (the variance, correlation radius, the length of the heterogenious region), but it also crucially depends on the metal substrate conductivity. For a small norm of the integral operator, the incident surface plasmon polariton (SPP) radiates effectively into vacuum, loosing the part of its energy for excitation of quasi-isotropic Norton-type waves above the conducting surface. The intensity of the leaking field is expressed in terms of the pair correlation function of the impedance, the dependence of which on wave numbers of incident and scattered waves demonstrates the possibility to observe a phenomenon similar to Wood's anomalies of wave scattering by periodic lattices. With strong scattering, when the norm of the scattering operator becomes large as compared to unity, the radiation into the volume is highly suppressed and the PPW is basically mirrored from the heterogeneous surface area in backward direction. In the model of dissipationless conducting halfspace, the surface plasmon-polariton becomes unstable for arbitrarily small fluctuations of the conductor polarizability. The mirroring also takes place at small norm of the scattering operator, yet in this case it is related to Anderson's localization of the SPP within the disordered region.

In the recent work [Dailey et al., Nature Astronomy 5, 150 (2021)], it was claimed that networks of quantum sensors can be used as sensitive multi-messenger probes of astrophysical phenomena that produce intense bursts of relativistic bosonic waves which interact non-gravitationally with ordinary matter. The most promising possibility considered in [Ibid.] involved clock-based searches for quadratic scalar-type interactions, with greatly diminished reach in the case of magnetometer-based searches for derivative-pseudoscalar-type interactions and clock-based searches for linear scalar-type interactions. In this note, we point out that the aforementioned work overlooked the ''back action'' of ordinary matter on scalar waves with quadratic interactions and that accounting for back-action effects can drastically affect the detection prospects of clock networks. In particular, back action can cause strong screening of scalar waves near Earth's surface and by the apparatus itself, rendering clock experiments insensitive to extraterrestrial sources of relativistic scalar waves. Additionally, back-action effects can retard the propagation of scalar waves through the interstellar and intergalactic media, significantly delaying the arrival of scalar waves at Earth compared to their gravitational-wave counterparts and thereby preventing multi-messenger astronomy on human timescales., Comment: 10 pages, 1 figure. Added rebuttal to arXiv:2112.02653v1 on page 9. Comment remains unchanged from v1