arXiv subjects

Eugene N. Ivanov

Publications and source records attributed to Eugene N. Ivanov.

At least 19 recordsLinked to original sources

arXiv2026

UPLOAD-HELIX: High-Helicity Single-Mode Microwave Haloscope with Low-Noise Interferometric Readout for Ultralight Axion Dark Matter

We propose a superconducting single-mode microwave haloscope based on chiral cavity resonators for the detection of ultralight dark matter axions over the mass range $4\times10^{-19}$-$~4\times10^{-14}\,\mathrm{eV}$. Building on the single-mode chiral-cavity concept introduced by Bourhill et al. [Phys. Rev. D 108, 052014 (2023); arXiv:2208.01640], we develop a resonator geometry compatible with subtractive manufacturing from high-purity bulk niobium, taking advantage of the substantially lower surface resistance achievable relative to the additively manufactured Möbius cavity proposed in the earlier work. An inverse-design framework is then used to maximise a figure of merit derived to minimise the measurement time required to achieve a fixed experimental sensitivity. The resulting optimised bulk-niobium design achieves a figure of merit more than three orders of magnitude larger than the additively manufactured Mobius benchmark. An experimentally informed microwave interferometric readout model, incorporating measured electronics noise and active suppression of pump amplitude noise, is used to project the sensitivity of the proposed experiment. For an acquisition time of three months, the haloscope is projected to reach $g_{aγγ}<10^{-11}\,\mathrm{GeV}^{-1}$ across more than four orders of magnitude in axion mass. The projected sensitivity extends approximately one order of magnitude below the current exclusion limits set by CAST, providing a practical pathway towards a high-sensitivity direct search for ultralight dark matter axions.

physics.ins-det↗

arXiv2026

A Search for Effects of Cosmic Rays with Multi-scale Entropy Metrics

We report a comparison of frequency fluctuations in oven-controlled quartz bulk-acoustic-wave oscillators operated above ground and one kilometre underground in a low-muon-background environment. The experiment is motivated by the possibility that cosmic rays and other ionizing-radiation backgrounds produce rare, impulsive energy-deposition events that perturb high-Q mechanical resonators and appear as intermittent, non-Gaussian structure in oscillator frequency noise. Conventional power spectral density and Allan-deviation analyses show no statistically compelling separation between the two environments over the explored timescales. In contrast, multi-scale sample entropy and its modified form reveal a pronounced divergence, with the underground data exhibiting increased predictability over a broad range of effective integration times. This result identifies a change in the temporal structure of the oscillator fluctuations that is largely hidden from standard second-order frequency-stability metrics. We therefore propose multi-scale sample entropy as a new diagnostic for frequency control and timing, complementary to Allan deviation and spectral analysis, with particular sensitivity to intermittent structure, non-stationary contributions, and rare-event contamination. The observed entropy separation also provides evidence that the above-ground cosmic-ray environment influences oscillator frequency fluctuations, suggesting that radiation-linked disturbances may contribute to the stochastic behaviour of precision mechanical oscillators. These findings introduce an entropy-based methodology for oscillator metrology and provide a practical tool for future fundamental-physics experiments using cryogenic resonant sensors, where rare-event backgrounds and poorly understood low-frequency noise can limit sensitivity.

physics.ins-det↗

arXiv2025

Near-quantum-limited axion dark matter search with the ORGAN experiment around 26 $μ$eV

The latest result from the ORGAN experiment, an axion haloscope is presented. This iteration of the experiment operated at millikelvin temperatures using a flux-driven Josephson parametric amplifier for reduced noise, along with various other improvements over previous iterations. Covering the $25.45 - 26.27\,μ\text{eV}$ ($6.15-6.35$ GHz) mass (frequency) range, this near-quantum limited phase of ORGAN employs a conducting rod resonator and a 7-T solenoidal magnet to place the most sensitive exclusion limits on axion-photon coupling in the range to date, with $|g_{aγγ}| \gtrsim 2.8\times10^{-13}$ at a 95\% confidence level.

hep-ex↗

arXiv2024

Microwave Cavity Mode Optimisation by Background Anti-Resonance Tuning

To derive the best oscillator phase noise when implementing a high-Q resonator, the spectral line-shape must have high contrast and symmetry. Ideally, this line-shape is Lorentzian, however, in a high mode density spectral region, low-Q background spurious modes interact and distort the resonance. For a sapphire-loaded cavity resonator operating with whispering gallery modes we show that this high contrast and symmetry can be achieved by changing the dimensions of the surrounding cavity shield to tune the background low-Q structures into anti-resonance. This works because the high-Q resonances are primarily defined by the sapphire while the background modes are defined by the cavity shield. Alternatively, it was shown that a similar result can be achieved by exciting the high-Q resonator with a balanced microwave dipole probe in a Mach Zehnder interferometric configuration. The probe was constructed from two separate coaxial electric field probes symmetrically inserted into a cylindrical cavity resonator, from opposite sides with a small gap between them, so they can behave like an active wire dipole antenna. The power into the two separate probes may be matched with an external variable attenuator in one of the arms of the interferometer. Conversely, the phase between the two electric field probes may be changed with an external variable phase shifter, which changes the nature of the field components the probe couples to. The probe couples to the high-Q resonant modes as well as low-Q background modes, which can be made resonant or anti-resonant for the high-Q modes by changing this external phase. When the background modes are in anti-resonance the line shape of the high-Q mode can be made symmetric and with higher contrast. This technique was applied to both whispering gallery sapphire modes, as well as hollow cavity resonators, without changing the dimensions of the cavity.

physics.app-ph↗

arXiv2024

Noise Suppression with Cryogenic Resonators

We show that fast technical fluctuations of microwave signals can be strongly suppressed by cryogenic resonators. The experiments were carried out with sapphire resonators cooled to approximately 6 K at frequencies around 11 GHz. Each sapphire crystal was shaped like a spindle with the rotational and crystal axes aligned within a degree. Noise suppression factors in excess of 50 dB were measured at 10 kHz offset from the carrier. This was achieved by rotating the sapphire spindle and moving the coupling probes relative to its surface. Microwave signals with reduced fast technical fluctuations allow the high-precision tests of fundamental physics, as well as the development of better radars.

physics.app-ph↗

arXiv2024

Frequency Stable Microwave Sapphire Oscillators

We show that state-of-the-art phase noise and high frequency stability could be simultaneously achieved in a microwave oscillator based on the sapphire-loaded cavity resonator. The 9 GHz sapphire oscillator was constructed with the SSB phase noise close to -170 dBc/Hz at an offset frequency of 10 kHz and fractional frequency instability less than 2 10$^{-13}$ for integration times from 5 to 50 s. In this work, we focus on the technique for phase-referencing the microwave sapphire oscillator to a stable radio-frequency source. We also discuss the suppression of the fast phase fluctuations of the microwave signal due to its transmission through the high-Q resonator.

physics.app-ph↗

arXiv2023

Exclusion of ALP Cogenesis Dark Matter in a Mass Window Above 100 $μ$eV

We report the results of Phase 1b of The ORGAN Experiment, a microwave cavity haloscope searching for dark matter axions in the $107.42-111.93~μ$eV mass range. The search excludes axions with two-photon coupling $g_{aγγ}\geq 4\times 10^{-12}\, \textrm{GeV}^{-1}$ with $95\%$ confidence interval, setting the best upper bound to date and with the required sensitivity to exclude the axion-like particle cogenesis model for dark matter in this range. This result was achieved using a tunable rectangular cavity, which mitigated several practical issues that become apparent when conducting high mass axion searches, and was the first such axion search to be conducted with such a cavity. It also represents the most sensitive axion haloscope experiment to date in the $\sim100~μ$eV mass region.

hep-ex↗

arXiv2023

Searching for Low-Mass Axions using Resonant Upconversion

We present new results of a room temperature resonant AC haloscope, which searches for axions via photon upconversion. Traditional haloscopes require a strong applied DC magnetic background field surrounding the haloscope cavity resonator, the resonant frequency of which is limited by available bore dimensions. UPLOAD, the UPconversion Low-Noise Oscillator Axion Detection experiment, replaces this DC magnet with a second microwave background resonance within the detector cavity, which upconverts energy from the axion field into the readout mode, accessing axions around the beat frequency of the modes. Furthermore, unlike the DC case, the experiment is sensitive to a newly proposed quantum electromagnetodynamical axion coupling term $g_{aBB}$. Two experimental approaches are outlined - one using frequency metrology, and the other using power detection of a thermal readout mode. The results of the power detection experiment are presented, which allows exclusion of axions of masses between 1.12 $-$ 1.20 $μeV$ above a coupling strength of both $g_{aγγ}$ and $g_{aBB}$ at $3 \times 10^{-6}$ 1/GeV, after a measurement period of 30 days, which is a three order of magnitude improvement over our previous result.

hep-ex↗

arXiv2022

Comparing Instrument Spectral Sensitivity of Dissimilar Electromagnetic Haloscopes to Axion Dark Matter and High Frequency Gravitational Waves

It is known that haloscopes that search for dark matter axions via the axion-photon anomaly are also sensitive to gravitational radiation through the inverse Gertsenshtein effect. Recently this way of searching for high frequency gravitational waves has gained momentum as it has been shown that the strain sensitivities of such detectors are of the same order of sensitivity to the axion-photon theta angle. Thus, after calculating the sensitivity of a haloscope to an axion signal, we also have calculated the order of magnitude sensitivity to a gravitational wave signal of the same spectral and temporal form. However, it is unlikely that a gravitational wave and an axion signal will be of the same form, since physically the way the signals are generated are completely different. For gravitational wave detection, the spectral strain sensitivity is in units strain per square root Hz, is the natural way to compare the sensitivity of gravitational wave detectors due to its independence on the gravitational wave signal. In this work, we introduce a systematic way to calculate the spectral sensitivity of an axion haloscope, so instrument comparison may be achieved independent of signal assumptions and only depends on the axion to signal transduction sensitivity and noise in the instrument. Thus, the calculation of the spectral sensitivity not only allows the comparison of dissimilar axion detectors independent of signal, but also allows us to compare the order of magnitude gravitational wave sensitivity in terms of spectral strain sensitivity, allowing comparisons to standard gravitational wave detectors based on optical interferometers and resonant-mass technology.

physics.ins-det↗

arXiv2022

Direct Search for Dark Matter Axions Excluding ALP Cogenesis in the 63-67 micro-eV Range, with The ORGAN Experiment

The standard model axion seesaw Higgs portal inflation (SMASH) model is a well motivated, self-contained description of particle physics over a range of energy scales that predicts axion dark matter particles to exist within the mass range of $50-200\,μ$eV. To scan these masses an axion haloscope under a strong constant magnetic field must operate between 12 to 48 GHz. The ORGAN experiment (situated in Perth, Australia) is a microwave cavity axion haloscope that aims to search the majority of the mass range predicted by the SMASH model. Here we present results of Phase 1a, the first experiment to scan and search for axions in the microwave Ku Band. Our initial scan sets a new limit on the coupling of axions to two photons of $g_{aγγ}\geq 3\times 10^{-12}\, \textrm{GeV}^{-1}$ over the mass range $63.2$ to $67.1~μ$eV with $95\%$ confidence. This result is the most sensitive to date in this mass range, sufficient to exclude the well motivated ALP (Axion Like Particle) cogenesis model for dark matter, which adds ALPs to the standard model in the early universe to simultaneously explain the observed baryon and dark matter densities. To attain this level of sensitivity we utilised a TM$_{010}$ cylindrical cavity resonator, scanned between 15.28 to 16.23 GHz through the utilisation of a tuning rod. Measurements were performed over a duration of 3.5 weeks with a $74\%$ duty cycle, with the resonator coupled to a low noise HEMT amplifier and placed inside a superconducting solenoidal electromagnet of 11.5 Tesla in magnetic field strength.

hep-ex↗

arXiv2021

Rare Events Detected with a Bulk Acoustic Wave High Frequency Gravitational Wave Antenna

This work describes the operation of a High Frequency Gravitational Wave detector based on a cryogenic Bulk Acoustic Wave (BAW) cavity and reports observation of rare events during 153 days of operation over two seperate experimental runs (Run 1 and Run 2). In both Run 1 and Run 2 two modes were simultaneously monitored. Across both runs, the 3rd overtone of the fast shear mode (3B) operating at 5.506 MHz was monitored, while in Run 1 the second mode was chosen to be the 5th OT of the slow shear mode (5C) operating at 8.392 MHz. However, in Run 2 the second mode was selected to be closer in frequency to the first mode, and chosen to be the 3rd overtone of the slow shear mode (3C) operating at 4.993 MHz. Two strong events were observed as transients responding to energy deposition within acoustic modes of the cavity. The first event occurred during Run 1 on the 12/05/2019 (UTC), and was observed in the 5.506 MHz mode, while the second mode at 8.392 MHz observed no event. During Run 2, a second event occurred on the 27/11/2019(UTC) and was observed by both modes. Timing of the events were checked against available environmental observations as well as data from other detectors. Various possibilities explaining the origins of the events are discussed.

gr-qc↗

arXiv2021

UPconversion Loop Oscillator Axion Detection experiment: A precision frequency interferometric axion dark matter search with a Cylindrical Microwave Cavity

First experimental results from a room-temperature table-top phase-sensitive axion haloscope experiment are presented. The technique exploits the axion-photon coupling between two photonic resonator-oscillators excited in a single cavity, allowing low-mass axions to be upconverted to microwave frequencies, acting as a source of frequency modulation on the microwave carriers. This new pathway to axion detection has certain advantages over the traditional haloscope method, particularly in targeting axions below 1 $μ$eV (240 MHz) in energy where high volume magnets are necessary. At the heart of the dual-mode oscillator, a tunable cylindrical microwave cavity supports a pair of orthogonally polarized modes ($\text{TM}_{\text{0,2,0}}$ and $\text{TE}_{\text{0,1,1}}$), which, in general, enables simultaneous sensitivity to axions with masses corresponding to the sum and difference of the microwave frequencies. The results place axion exclusion limits between 7.44 - 19.38 neV, excluding a minimal coupling strength above $3\times 10^{-3}$ 1/GeV, and between 74.4 - 74.5 $μ$eV, excluding a minimal coupling strength above $10^{-2}$ 1/GeV, after a measurement period of two and a half hours. We show that a state-of-the-art frequency-stabilized cryogenic implementation of this technique may achieve competitive limits in a large range of axion-space.

hep-ex↗

arXiv2021

Searching for Scalar Dark Matter via Coupling to Fundamental Constants with Photonic, Atomic and Mechanical Oscillators

We present a way to search for light scalar dark matter (DM), seeking to exploit putative coupling between dark matter scalar fields and fundamental constants, by searching for frequency modulations in direct comparisons between frequency stable oscillators. Specifically we compare a Cryogenic Sapphire Oscillator (CSO), Hydrogen Maser (HM) atomic oscillator and a bulk acoustic wave quartz oscillator (OCXO). This work includes the first calculation of the dependence of acoustic oscillators on variations of the fundamental constants, and demonstration that they can be a sensitive tool for scalar DM experiments. Results are presented based on 16 days of data in comparisons between the HM and OCXO, and 2 days of comparison between the OCXO and CSO. No evidence of oscillating fundamental constants consistent with a coupling to scalar dark matter is found, and instead limits on the strength of these couplings as a function of the dark matter mass are determined. We constrain the dimensionless coupling constant $d_e$ and combination $|d_{m_e}-d_g|$ across the mass band $4.4\times10^{-19}\lesssim m_φ\lesssim 6.8\times10^{-14}\:\text{eV} c^{-2}$, with most sensitive limits $d_e\gtrsim1.59\times10^{-1}$, $|d_{m_e}-dg|\gtrsim6.97\times10^{-1}$. Notably, these limits do not rely on Maximum Reach Analysis (MRA), instead employing the more general coefficient separation technique. This experiment paves the way for future, highly sensitive experiments based on state-of-the-art acoustic oscillators, and we show that these limits can be competitive with the best current MRA-based exclusion limits.

hep-ex↗

arXiv2020

Generation of Spectrally Pure Microwave Signals

Based on the principles of microwave circuit interferometry we have constructed a Reduced Noise Amplifier (RNA) with power spectral density of phase, as well as amplitude, fluctuations close to -170 dBc/Hz at 1 kHz offset. The RNA has been incorporated with a cryogenic sapphire resonator as a loop oscillator whose noise performance is governed by the Leeson's model. Following this model and using the results of in-situ measurements of gain and phase fluctuations of the RNA we inferred noise properties of the oscillator. In particular, for a signal transmitted through the resonator we found that power spectral density of its phase/amplitude fluctuations must be close to -185 dBc/Hz at offsets above 300 Hz. We discuss a few approaches that will allow direct measurements of such low levels of noise.

physics.ins-det↗

arXiv2019

Cross-correlation measurement techniques for cavity-based axion and weakly interacting slim particle searches

The search for dark matter is of fundamental importance to our understanding of the universe. Weakly-Interacting Slim Particles (WISPs) such as axions and hidden sector photons (HSPs) are well motivated candidates for the dark matter. Some of the most sensitive and mature experiments to detect WISPs rely on microwave cavities, and the detection of weak photon signals. It is often suggested to power combine multiple cavities, which creates a host of technical concerns. We outline a scheme based on cross-correlation for effectively power combining cavities and increasing the signal-to-noise ratio of a candidate WISP signal.

physics.ins-det↗

arXiv2018

Broadband Axion Dark Matter Haloscopes via Electric Sensing

The mass of axion dark matter is only weakly bounded by cosmological observations, necessitating a variety of detection techniques over several orders of magnitude of mass ranges. Axions haloscopes based on resonant cavities have become the current standard to search for dark matter axions. Such structures are inherently narrowband and for low masses the volume of the required cavity becomes prohibitively large. Broadband low-mass detectors have already been proposed using inductive magnetometer sensors and a gapped toroidal solenoid magnet. In this work we propose an alternative, which uses electric sensors in a conventional solenoidal magnet aligned in the laboratory z-axis, as implemented in standard haloscope experiments. In the presence of the DC magnetic field, the inverse Primakoff effect causes a time varying permanent electric vacuum polarization in the z-direction to oscillate at the axion Compton frequency, which induces an oscillating electromotive force. We propose non-resonant techniques to detect this oscillating elctromotive force by implementing a capacitive sensor or an electric dipole antenna coupled to a low noise amplifier. We present the first experimental results and discuss the foundations and potential of this proposal. Preliminary results constrain $g_{aγγ} >\sim2.35\times10^{-12}$ $\text{GeV}^{-1}$ in the mass range of $2.08\times10^{-11}$ to $2.2\times10^{-11}$ eV, and demonstrate potential sensitivity to axion-like dark matter with masses in the range of $10^{-12}$ to $10^{-8}$ eV.

physics.ins-det↗

arXiv2018

Next Generation of Phonon Tests of Lorentz Invariance using Quartz BAW Resonators

We demonstrate technological improvements in phonon sector tests of Lorentz Invariance that implement quartz Bulk Acoustic Wave oscillators. In this experiment, room temperature oscillators with state-of-the-art phase noise are continuously compared on a platform that rotates at a rate of order a cycle per second. The discussion is focused on improvements in noise measurement techniques, data acquisition and data processing. Preliminary results of the second generation of such tests are given, and indicate that SME coefficients in the matter sector can be measured at a precision of order $10^{-16}$ GeV after taking a years worth of data. This is equivalent to an improvement of two orders of magnitude over the prior acoustic phonon sector experiment.

physics.ins-det↗

arXiv2018

Inducing Strong Non-Linearities in a Phonon Trapping Quartz Bulk Acoustic Wave Resonator Coupled to a Superconducting Quantum Interference Device

A quartz Bulk Acoustic Wave resonator is designed to coherently trap phonons in a way that they are well confined and immune to suspension losses so they exhibit extremely high acoustic $Q$-factors at low temperature, with $Q\times f$ products of order $10^{18}$ Hz. In this work we couple such a resonator to a SQUID amplifier and investigate effects in the strong signal regime. Both parallel and series connection topologies of the system are investigated. The study reveals significant non-Duffing response that is associated with the nonlinear characteristics of Josephson junctions. The nonlinearity provides quasi-periodic structure of the spectrum in both incident power and frequency. The result gives an insight into the open loop behaviour of a future Cryogenic Quartz Oscillator in the strong signal regime.

physics.ins-det↗