Extending the fundamental limit of atomic clock stability

• URL: http://arxiv.org/abs/2604.01099v1
• Date: Wed, 01 Apr 2026 16:24:28 GMT
• Title: Extending the fundamental limit of atomic clock stability
• Abstract summary: We analyze a model that includes noise sources - quantum projection noise and spontaneous decay from the excited state.<n>This model allows for detection and exclusion of atomic frequency interrogations in which the atom decayed.<n>We identify an even greater stability enhancement of $approx 5.4 text dB$ for frequency comparisons between atoms in an odd parity Bell state.
• Score: 2.1109785563235555
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Optical atomic clocks have been rapidly developing in recent decades, resulting in major improvements in both precision and accuracy. As a result, they have become instrumental in multiple areas of applied and fundamental research. Despite all atomic frequency references having more than two energy-levels, the commonly used model for evaluating their ultimate limits assumes a two-level atom. This leads to frequency interrogation protocols and theoretical stability bounds that are suboptimal for a true multi-level atom. The most fundamental stability bound assumes two noise sources - quantum projection noise and spontaneous decay from the excited state. In this work, we analyze a model that includes these noise types and is generalized beyond the two-level assumption, where spontaneous decay can branch to more than a single ground state. This model allows for detection and exclusion of atomic frequency interrogations in which the atom decayed, leading to a frequency stability improvement of up to $\approx 4.5 \text{ dB}$ compared with the two-level model. Furthermore, we identify an even greater stability enhancement of $\approx 5.4 \text{ dB}$ for frequency comparisons between atoms in an odd parity Bell state. These enhancements are particularly relevant for the numerous trapped-ion optical clock species that operate close to lifetime-limited stability. We calculate new stability limits for those cases and provide a detailed experimental protocol for frequency interrogation with an $^{27}\text{Al}^{+}$ optical ion clock.

Related papers

• Qutrit entanglement and joint multi-parameter estimation in an optical clock platform [2.2470290096767003]
  We experimentally demonstrate genuine qutrit entanglement and joint multi- parameter estimation in an optical clock platform.<n>Taking advantage of this high-dimensional entanglement, we realize an optimal two-qutrit metrological probe state and noise-robust readout circuit.<n>These results demonstrate the key building blocks towards quantum information science with high-dimensional states encoded in the internal energy levels of neutral atoms.
  arXiv  Detail & Related papers  (2026-08-05T21:41:06Z)
• Multirate characterization of relaxation mechanisms for two nonequivalent nuclear spins 1/2 in a liquid using maximally entangled pseudo-pure quantum states [41.99844472131922]
  Multirate characterization of spin responses in nuclear magnetic resonance (NMR) is a promising approach to fingerprinting complex molecules.<n>We present experimental and theoretical investigations simultaneously accessing 8 relaxation rates describing the density matrix of two adjacent nonequivalent nuclear spins.
  arXiv  Detail & Related papers  (2026-04-29T21:42:37Z)
• Atomic clock frequency ratios with fractional uncertainty $\leq 3.2 \times 10^{-18}$ [26.478584624026112]
  We report high-precision frequency ratio measurements between optical atomic clocks based on $27$Al$+$, $171$Yb, and $87$Sr.<n>With total fractional uncertainties at or below $3.2 times 10-18$, these measurements meet an important milestone criterion for redefinition of the second in the International System of Units.
  arXiv  Detail & Related papers  (2025-12-24T21:25:48Z)
• High-fidelity entanglement and coherent multi-qubit mapping in an atom array [34.82692226532414]
  We show the creation and coherent mapping of entangled quantum states across multiple qubits in Ytterbium-171 tweezer arrays.<n>Results establish a versatile architecture that advances multiple fields of quantum information science while also establishing bridges between them.
  arXiv  Detail & Related papers  (2025-06-16T15:58:53Z)
• Extending the coherence time limit of a single-alkali-atom qubit by suppressing phonon-jumping-induced decoherence [22.585565798915038]
  Coherence time of qubit encoded in electronic states is one of the most important parameters.<n>Coherence time is assumed to be determined by relative stability of the energy between the electronic states.<n>We propose a complete description of the decoherence of a qubit encoded in two ground electronic states of an optically trapped alkali atom.
  arXiv  Detail & Related papers  (2023-12-18T13:42:46Z)
• Finite Pulse-Time Effects in Long-Baseline Quantum Clock Interferometry [45.73541813564926]
  We study the interplay of the quantum center-of-mass $-$ that can become delocalized $-$ together with the internal clock transitions. We show at the example of a Gaussian laser beam that the proposed quantum-clock interferometers are stable against perturbations from varying optical fields.
  arXiv  Detail & Related papers  (2023-09-25T18:00:03Z)
• Wavefront Curvature in Optical Atomic Beam Clocks [0.0]
  Recent demonstrations of compact optical clocks, employing thermal atomic beams, have achieved short-term fractional frequency instabilities in the $10-16$. A serious challenge inherent in compact clocks is the necessarily smaller optical beams, which results in rapid variation in interrogating wavefronts. Here we develop a model for Ramsey-Bord'e interferometery using optical fields with curved wavefronts.
  arXiv  Detail & Related papers  (2022-12-01T06:57:23Z)
• Correlated steady states and Raman lasing in continuously pumped and probed atomic ensembles [68.8204255655161]
  We consider an ensemble of Alkali atoms that are continuously optically pumped and probed. Due to the collective scattering of photons at large optical depth, the steady state of atoms does not correspond to an uncorrelated tensor-product state. We find and characterize regimes of Raman lasing, akin to the model of a superradiant laser.
  arXiv  Detail & Related papers  (2022-05-10T06:54:54Z)
• Universality-of-clock-rates test using atom interferometry with $T^{3}$ scaling [63.08516384181491]
  Atomic clocks generate delocalized quantum clocks. Tests of universality of clock rates (one facet of LPI) to atom interferometry generating delocalized quantum clocks proposed. Results extend our notion of time, detached from classical and localized philosophies.
  arXiv  Detail & Related papers  (2022-04-05T12:26:56Z)
• Spontaneous decay induced quantum dynamics in Rydberg blockaded {\Lambda}-type atoms [0.0]
  Rydberg-blockaded two-level atoms form a Rydberg superatom. spontaneous decay from the Rydberg state to an additional pooling state renders the ensemble no longer a closed superatom. We present a computationally-efficient model to characterize the interaction between a fully Rydberg-blockaded ensemble of $N$ $Lambda$-type three-level atoms.
  arXiv  Detail & Related papers  (2021-12-18T11:01:32Z)
• Improved absolute clock stability by the joint interrogation of two atomic states [0.7582991335459645]
  We propose a strategy to improve the stability of atomic clocks by interrogating two out-of-phase state sharing the same LO. Our protocol can be readily tested in current state-of-the-art experiments.
  arXiv  Detail & Related papers  (2021-04-29T12:50:28Z)
• Stabilization of Qubit Relaxation Rates by Frequency Modulation [68.8204255655161]
  Temporal, spectral, and sample-to-sample fluctuations in coherence properties of qubits form an outstanding challenge for the development of upscaled fault-tolerant quantum computers. A ubiquitous source for these fluctuations in superconducting qubits is a set of atomic-scale defects with a two-level structure. We show that frequency modulation of a qubit or, alternatively, of the two-level defects, leads to averaging of the qubit relaxation rate over a wide interval of frequencies.
  arXiv  Detail & Related papers  (2021-04-08T11:32:03Z)
• Electronic decay process spectra including nuclear degrees of freedom [49.1574468325115]
  We explore the ultra-rapid electronic motion spanning attoseconds to femtoseconds, demonstrating that it is equally integral and relevant to the discipline. The advent of ultrashort attosecond pulse technology has revolutionized our ability to directly observe electronic rearrangements in atoms and molecules.
  arXiv  Detail & Related papers  (2021-02-10T16:51:48Z)
• Fast high-fidelity single-qubit gates for flip-flop qubits in silicon [68.8204255655161]
  flip-flop qubit is encoded in the states with antiparallel donor-bound electron and donor nuclear spins in silicon. We study the multilevel system that is formed by the interacting electron and nuclear spins. We propose an optimal control scheme that produces fast and robust single-qubit gates in the presence of low-frequency noise.
  arXiv  Detail & Related papers  (2021-01-27T18:37:30Z)
• Nuclear clocks for testing fundamental physics [0.0]
  The low-energy, long-lived isomer in $229$Th continues to inspire a multidisciplinary community of physicists. It is possible to build a highly precise nuclear clock based on resonant of the electron shell. The nuclear clock will open opportunities for highly sensitive tests of fundamental principles of physics.
  arXiv  Detail & Related papers  (2020-12-16T22:45:59Z)
• Heisenberg-limited noisy atomic clock using a hybrid coherent and squeezed states protocol [0.0]
  We propose a hybrid quantum-classical atomic clock protocol where the interrogation of an ensemble of uncorrelated atoms in a spin-coherent state is used to feedback one (or more) spin-squeezed atomic ensembles toward their optimal phase sensitivity point. This protocol overcomes the stability of a single Ramsey clock and it reaches a Heisenberg-limited stability while avoiding non-destructive measurements.
  arXiv  Detail & Related papers  (2020-03-24T16:16:26Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.