Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Beating the Heisenberg limit in a single atom for dark matter search

Tarun Dutta, Manas Mukherjee

Published Mar 5, 2018• 0 citations
OpenAlex

Abstract

Quantum metrology for frequency measurement has been used to surpass the Heisenberg scaling of the measurement uncertainty with observation time. In a single ion experiment, we show that the uncertainty in the frequency measurement scales as $1/T^2$ for over 100 $\mu$s time scale limited by the de-phasing time of the probe state. The proof-of-principle experiment also sets a limit on the coupling strength of axion like dark matter particle wind to interact with an electron spin. Even though the limit is a weak limit, we provide feasible experiment by which the limit can be strengthened to complement the other dark matter search experiments. The scheme is based on the proposal by Pang et al.~\cite{Pang2017} implemented on a laser cooled single ion probe which has been subjected to an external time dependent field coupling.

Related papers

A single atom noise probe operating beyond the Heisenberg limit

Tarun Dutta, M. Mukherjee

Abstract According to the Heisenberg uncertainty principle, the energy or frequency uncertainty of a measurement can be at the best inversely proportional to the observation time ( $$T$$ T ). The observation time in an experiment using a quantum mechanical probe is ultimately limited by the coherence time of the probe. Therefore the inverse proportionality of the statistical uncertainty of a frequency measurement to the observation time is also limited up to the coherence time of the probe, provided the systematic uncertainties are well below the statistical uncertainties. With a single laser-cooled barium ion as a quantum probe, we show that the uncertainty in the frequency measurement for a general time-dependent Hamiltonian scales as $$1/{T}^{1.75\pm 0.03}$$ 1 ∕ T 1.75 ± 0.03 as opposed to $$1/T$$ 1 ∕ T , given by the Heisenberg limit for time-independent Hamiltonian. These measurements, based on controlled feedback Hamiltonian and implemented on a laser cooled single ion, allowed precise measurement of noise frequency in the kHz range. Moreover, based on the observed sensitivity of a single ion experiment presented here, we propose the use of a similar protocol with enhanced sensitivity as a tool to directly verify the existence of certain types of light mass axion-like dark matter particles where no direct measurement protocol exists.

arXiv:1803.01724•npj Quantum Information•Jan 8, 2020•6 citations

Super-Heisenberg protocol for dark matter and high-frequency gravitational wave search

Wakutaka Nakano, Ryoto Takai

We propose a quantum-enhanced sensing scheme for the detection of wave-like dark matter and high-frequency gravitational waves using two-dimensional ion crystals in a Penning trap. The protocol employs spin-motion squeezed states to improve the signal-to-noise ratio and enable a super-Heisenberg scaling with respect to the number of ions over a broad parameter range. We analyze the sensitivity of the protocol to representative wave-like dark matter candidates, including the axion-like particle and the dark photon, as well as to high-frequency gravitational waves, taking into account the decoherence and dephasing of the ion spins. Our results indicate that two-dimensional ion crystals and this new protocol provide a promising platform for probing previously unexplored parameter space in searches for light dark matter and high-frequency gravitational waves.

hep-phCross-listedarXiv:2604.22336•Physical review. D/Physical review. D.•Apr 27, 2026•0 citations

Searching for axion dark matter with magnetic resonance force microscopy

Elham Kashi, Muhammad Hani Zaheer, Ryan Petery +1 more

We propose a magnetic resonance force microscopy (MRFM) search for axion dark matter around 1 GHz. The experiment leverages the axion's derivative coupling to electrons, which induces an effective A.C. magnetic field on a sample of electron spins polarized by a D.C. magnetic field and a micromagnet. A second pump field at a nearby frequency enhances the signal, with the detuning matched to the resonant frequency of a magnet-loaded mechanical oscillator. The resulting spin-dependent force is detected with hih sensitivity via optical interferometry. Accounting for the relevant noise sources, we show that current technology can be used to put constraints competitive with those from laboratory experiments with just a minute of integration time. Furthermore, varying the pump field frequency and D.C. magnetic field allows one to scan the axion mass. Finally, we explore this setup's capability to put constraints on other dark matter - Standard Model couplings.

hep-phCross-listedarXiv:2512.12120•Dec 16, 2025

Axion detection in the non-Markovian noise

Jing Dong, Shuang-Quan Ma, Rong-Hang Chen +4 more

The detection of axion dark matter poses a significant challenge due to its exceptionally weak coupling to standard-model particles. Here we develop a noise-tolerant quantum-metrology scheme based on coupled $^{129}$Xe spin ensembles to search for such weakly interacting particles. Within an experimentally accessible parameter regime, our scheme achieves an ideal exclusion limit on the axion coupling constant that is several orders of magnitude more stringent than that of conventional detection methods. We further investigate the performance of our scheme under dissipative noise and find that its robustness is fundamentally governed by the energy-spectrum structure of the composite spin-environment system. Remarkably, when a bound state emerges in the spectrum, the exclusion limit asymptotically recovers its ideal value in the non-Markovian dynamics, whereas under the Markovian approximation the limit deteriorates significantly due to noise. Our results establish a universal mechanism for noise-resilient exploration of beyond-standard-model physics, which can be practically implemented by engineering bound-state formation via tuning the Larmor frequency of the spin ensembles.

quant-pharXiv:2610.27731•Oct 21, 2026•0 citations

Achieving Heisenberg scaling by probe-ancilla interaction in quantum metrology

Jingyi Fan, Shengshi Pang

The Heisenberg scaling is an ultimate precision limit of parameter estimation allowed by the principles of quantum mechanics, with no counterpart in the classical realm, and has been a long-pursued goal in quantum metrology. It has been known that interactions between the probes can help reach the Heisenberg scaling without entanglement. In this paper, we show that interactions between the probes and the additional dimensions of an ancillary system may also increase the precision of parameter estimation to surpass the standard quantum limit and attain the Heisenberg scaling without entanglement, if the measurement scheme is properly designed. The quantum Fisher information exhibits periodic patterns over the evolution time, implying the existence of optimal time points for measurements that can maximize the quantum Fisher information. By implementing optimizations over the Hamiltonian, the initial states of the probes and the ancillary system, the interaction strength, and the time points for measurements, our protocol achieves the Heisenberg scaling for the parameter of the probe Hamiltonian, in terms of both evolution time and probe number. Our protocol features two aspects: (i) the Heisenberg scaling can be achieved by a product state of the probes and (ii) mere local measurement on the ancilla is sufficient, both of which reduce the quantum resources and the implementation complexity to achieve the Heisenberg scaling. The paper is concluded by the investigation of the effects of noise on this protocol.

arXiv:2407.16880•Physical Review A•Dec 3, 2024•6 citations

Benchmarking Dark Matter Search using a Parity-Check Protocol with Machine-Learning Optimized Pulses

Yu-Han Chang, Ilya Moskalenko, Marko Kuzmanović +7 more

We report on an improved microwave detection protocol for dark matter candidates such as the axion and the dark photon. We employ a superconducting transmon qubit dispersively coupled to a double-cavity system, enabling quantum non-demolition measurements of the photon occupation in a relatively short-lived storage cavity. To reduce the experimental cycle time and enhance sensitivity for axion and dark-photon searches, we operate this detector in a regime of increased qubit-cavity coupling, resulting in Stark shifts of 4.6 MHz. In this regime, conventional control pulses suffer from strong frequency-detuning sensitivity and photon-number-dependent errors. We address this limitation by implementing frequency-detuning-robust $π/2$ pulses (obtained by machine-learning optimization) that preserve high-fidelity qubit control over a bandwidth of approximately 20 MHz. We experimentally validate this protocol and demonstrate single-photon detection performance comparable to previous implementations, despite significantly reduced qubit coherence times and storage-cavity lifetimes. Using parity-based measurement sequences combined with a Hidden Markov Model (HMM) analysis, we achieve background rates on the order of $\mathcal{O}(20)$ Hz. In the absence of a magnetic field, we derive exclusion limits on the dark photon model for dark matter, reaching a sensitivity to the kinetic mixing angle of $ε_{95\%} \sim 1\times10^{-14}$ at 5.051 GHz. These results establish machine-learning robust control as a key enabler for faster, more scalable microwave quantum sensors for dark-matter searches.

quant-pharXiv:2606.25795•Physical review. D/Physical review. D.•Jun 25, 2026•0 citations
Quantum metrology for frequency measurement has been used to surpass the
Heisenberg scaling of the measurement uncertainty with observation time. In a
single ion experiment, we show that the uncertainty in the frequency
measurement scales as 1/T21/T^21/T2 for over 100 μ\muμs time scale limited by the
de-phasing time of the probe state. The proof-of-principle experiment also sets
a limit on the coupling strength of axion like dark matter particle wind to
interact with an electron spin. Even though the limit is a weak limit, we
provide feasible experiment by which the limit can be strengthened to
complement the other dark matter search experiments. The scheme is based on the
proposal by Pang et al.~\cite{Pang2017} implemented on a laser cooled single
ion probe which has been subjected to an external time dependent field
coupling.
Abstract According to the Heisenberg uncertainty principle, the energy or frequency uncertainty of a measurement can be at the best inversely proportional to the observation time ( TTT T ). The observation time in an experiment using a quantum mechanical probe is ultimately limited by the coherence time of the probe. Therefore the inverse proportionality of the statistical uncertainty of a frequency measurement to the observation time is also limited up to the coherence time of the probe, provided the systematic uncertainties are well below the statistical uncertainties. With a single laser-cooled barium ion as a quantum probe, we show that the uncertainty in the frequency measurement for a general time-dependent Hamiltonian scales as 1/T1.75±0.031/{T}^{1.75\pm 0.03}1/T1.75±0.03 1 ∕ T 1.75 ± 0.03 as opposed to 1/T1/T1/T 1 ∕ T , given by the Heisenberg limit for time-independent Hamiltonian. These measurements, based on controlled feedback Hamiltonian and implemented on a laser cooled single ion, allowed precise measurement of noise frequency in the kHz range. Moreover, based on the observed sensitivity of a single ion experiment presented here, we propose the use of a similar protocol with enhanced sensitivity as a tool to directly verify the existence of certain types of light mass axion-like dark matter particles where no direct measurement protocol exists.
We propose a quantum-enhanced sensing scheme for the detection of wave-like dark matter and high-frequency gravitational waves using two-dimensional ion crystals in a Penning trap. The protocol employs spin-motion squeezed states to improve the signal-to-noise ratio and enable a super-Heisenberg scaling with respect to the number of ions over a broad parameter range. We analyze the sensitivity of the protocol to representative wave-like dark matter candidates, including the axion-like particle and the dark photon, as well as to high-frequency gravitational waves, taking into account the decoherence and dephasing of the ion spins. Our results indicate that two-dimensional ion crystals and this new protocol provide a promising platform for probing previously unexplored parameter space in searches for light dark matter and high-frequency gravitational waves.
We propose a magnetic resonance force microscopy (MRFM) search for axion dark matter around 1 GHz. The experiment leverages the axion's derivative coupling to electrons, which induces an effective A.C. magnetic field on a sample of electron spins polarized by a D.C. magnetic field and a micromagnet. A second pump field at a nearby frequency enhances the signal, with the detuning matched to the resonant frequency of a magnet-loaded mechanical oscillator. The resulting spin-dependent force is detected with hih sensitivity via optical interferometry. Accounting for the relevant noise sources, we show that current technology can be used to put constraints competitive with those from laboratory experiments with just a minute of integration time. Furthermore, varying the pump field frequency and D.C. magnetic field allows one to scan the axion mass. Finally, we explore this setup's capability to put constraints on other dark matter - Standard Model couplings.
The detection of axion dark matter poses a significant challenge due to its exceptionally weak coupling to standard-model particles. Here we develop a noise-tolerant quantum-metrology scheme based on coupled 129^{129}129Xe spin ensembles to search for such weakly interacting particles. Within an experimentally accessible parameter regime, our scheme achieves an ideal exclusion limit on the axion coupling constant that is several orders of magnitude more stringent than that of conventional detection methods. We further investigate the performance of our scheme under dissipative noise and find that its robustness is fundamentally governed by the energy-spectrum structure of the composite spin-environment system. Remarkably, when a bound state emerges in the spectrum, the exclusion limit asymptotically recovers its ideal value in the non-Markovian dynamics, whereas under the Markovian approximation the limit deteriorates significantly due to noise. Our results establish a universal mechanism for noise-resilient exploration of beyond-standard-model physics, which can be practically implemented by engineering bound-state formation via tuning the Larmor frequency of the spin ensembles.
The Heisenberg scaling is an ultimate precision limit of parameter estimation allowed by the principles of quantum mechanics, with no counterpart in the classical realm, and has been a long-pursued goal in quantum metrology. It has been known that interactions between the probes can help reach the Heisenberg scaling without entanglement. In this paper, we show that interactions between the probes and the additional dimensions of an ancillary system may also increase the precision of parameter estimation to surpass the standard quantum limit and attain the Heisenberg scaling without entanglement, if the measurement scheme is properly designed. The quantum Fisher information exhibits periodic patterns over the evolution time, implying the existence of optimal time points for measurements that can maximize the quantum Fisher information. By implementing optimizations over the Hamiltonian, the initial states of the probes and the ancillary system, the interaction strength, and the time points for measurements, our protocol achieves the Heisenberg scaling for the parameter of the probe Hamiltonian, in terms of both evolution time and probe number. Our protocol features two aspects: (i) the Heisenberg scaling can be achieved by a product state of the probes and (ii) mere local measurement on the ancilla is sufficient, both of which reduce the quantum resources and the implementation complexity to achieve the Heisenberg scaling. The paper is concluded by the investigation of the effects of noise on this protocol.
We report on an improved microwave detection protocol for dark matter candidates such as the axion and the dark photon. We employ a superconducting transmon qubit dispersively coupled to a double-cavity system, enabling quantum non-demolition measurements of the photon occupation in a relatively short-lived storage cavity. To reduce the experimental cycle time and enhance sensitivity for axion and dark-photon searches, we operate this detector in a regime of increased qubit-cavity coupling, resulting in Stark shifts of 4.6 MHz. In this regime, conventional control pulses suffer from strong frequency-detuning sensitivity and photon-number-dependent errors. We address this limitation by implementing frequency-detuning-robust π/2π/2π/2 pulses (obtained by machine-learning optimization) that preserve high-fidelity qubit control over a bandwidth of approximately 20 MHz. We experimentally validate this protocol and demonstrate single-photon detection performance comparable to previous implementations, despite significantly reduced qubit coherence times and storage-cavity lifetimes. Using parity-based measurement sequences combined with a Hidden Markov Model (HMM) analysis, we achieve background rates on the order of O(20)\mathcal{O}(20)O(20) Hz. In the absence of a magnetic field, we derive exclusion limits on the dark photon model for dark matter, reaching a sensitivity to the kinetic mixing angle of ε95%∼1×10−14ε_{95\%} \sim 1\times10^{-14}ε95%​∼1×10−14 at 5.051 GHz. These results establish machine-learning robust control as a key enabler for faster, more scalable microwave quantum sensors for dark-matter searches.