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Journal articleJae J, Lee J, Kim MS, et al., 2026, , Npj Quantum Information, Vol: 12
Correction to: npj Quantum Informationhttps://doi.org/10.1038/s41534-024-00862-5, published online 04 July 2024 In the original article, the authors followed the standard criterion for estimation precision based on the observed Fisher information. However, the data structure of the contextual quantum metrology (coQM) framework is constructed from an operational quasiprobability model, which does not coincide with the sampling distribution of the measurements
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Journal articleKukreja P, Agarwal P, Doppelbauer M, et al., 2026, , New Journal of Physics
<jats:title>Abstract</jats:title> <jats:p> The AlF molecule, currently subject to laser cooling and trapping efforts, has the advantage that it can be efficiently produced in a thermochemical reaction between sublimated aluminum trifluoride and aluminum metal. Here we present a series of experiments with continuous molecular beam sources of AlF, utilising this reaction. We demonstrate a compact AlF molecular beam oven whose total far-field brightness is 5 × 10 <jats:sup>15</jats:sup> molecules per steradian per second at 923 K, just below the melting temperature of aluminum metal. The continuous output from the oven begins to exceed the peak brightness of a jet-cooled, ablation-based supersonic AlF source for the <jats:italic>v</jats:italic> = 0, <jats:italic>J</jats:italic> = 7 level, and we obtain an excellent signal-to-noise ratio with the oven in pulsed laser ionisation spectroscopy experiments. By delivering flux from the oven into a cryogenic Ne buffer gas cell, we lower the rotational temperature of the beam to around 30 K and reduce its most probable forward velocity from 600 m/s to 200 m/s. In addition, we demonstrate that AlF can be made in a simple dispenser package, and observe that molecules thermalise to the laboratory temperature after colliding with vacuum chamber walls of the experiment. The resulting transient AlF vapour may enable direct loading of a molecular magneto-optical trap. </jats:p>
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Journal articleMorhayim E, Ziemba MT, Lim J, et al., 2026, , Physical Review A, Vol: 113, ISSN: 2469-9926
<jats:p>We consider stimulated Raman adiabatic passage when the final state is a superposition of two nondegenerate states. The system consists of four states coupled by two light fields. We find the relative phase of the final superposition depends on the relative amplitude, width, and timing of the adiabatic transfer pulses. We discuss these results in the context of experiments measuring symmetry violation in atomic and molecular systems.</jats:p>
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Journal articleLyu Q, Tarbutt M, 2026, , Physical Review Research
In red-detuned magneto-optical traps (MOTs) of molecules, sub-Doppler heating competes with Doppler cooling, resulting in high temperature and low density. A solution is offered by the blue-detuned MOT where sub-Doppler cooling dominates and the cloud is compressed. Several blue-detuned molecular MOTs have been implemented. A recent implementation relies on a pair of orthogonally polarized components whose frequency separation is smaller than the transition linewidth. We identify the trapping force in these MOTs. At a certain magnetic field, there is a state that is dark to the laser propagating in one direction, but not to the counter-propagating one. This Zeeman-induced dark state (ZIDS) sets up an imbalance in the photon scattering rate, leading to a restoring force. We also study the role of the moving lattices generated by the closely-spaced frequency components of the light. We show that there is a velocity-dependent force that drives the molecules towards the speeds of these moving lattices, and that over a relevant range of magnetic fields this combines with the ZIDS force to transport molecules towards the centre of the MOT. Here, gray molasses cooling, assisted by non-adiabatic transitions driven by the time-varying polarization of the light field, cools the molecules towards zero velocity. We study these mechanisms for model systems with simple level structures, then extend them to molecules with ground state hyperfine structure.
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Journal articleHo C, Dutta J, Mukherjee B, et al., 2026, , Physical Review Research, ISSN: 2643-1564
The ability to tune interparticle interactions is one of the main advantages of using ultracold quantum gases forquantum simulation of many-body physics. Current experiments with ultracold polar molecules employ shielding with microwave or static electric fields to prevent destructive collisional losses. The interaction potential ofmicrowave-shielded molecules can be tuned by using microwaves of two different polarizations, while for static-field-shielded molecules the tunability of interactions is more limited and depends on the particular species.In this work, we propose a general method to tune the interactions between static-field-shielded molecules byapplying a microwave field. We carry out coupled-channel scattering calculations in a field-dressed basis set todetermine loss rate coefficients and scattering lengths. We find that both the s-wave scattering length and thedipole length can be widely tuned by changing the parameters of the microwave field, while maintaining strong suppression of lossy collisions.
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Journal articleKowalczyk KM, Wyatt AS, Allegre H, et al., 2026, , APL Photonics, Vol: 11
High harmonic generation in crystals is a strong-field process that can be used to probe the electronic structure and dynamics of solids and promises a route to attosecond control in the condensed phase. Here, we investigate the complex spatiospectral structures in high harmonics generated from MgO crystals in transmission geometry. We explore the patterns within individual harmonics as a function of laser intensity. Using z-scan analysis, we retrieve the nonlinear refractive index and employ propagation calculations to examine the transverse spatial coherence model, consistent with the interband dominated harmonic emission, as the source of these patterns. We find that the inclusion of the nonlinear propagation effects explains the structures well, without requiring a multi-trajectory interference or changing dephasing times.
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Journal articleKnight PL, Raymer M, Vitanov NV, 2026, , Journal of Physics B Atomic Molecular and Optical Physics, Vol: 59, ISSN: 0953-4075
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Conference paperWebber-Date A, Rowley M, Osborn PF, et al., 2026, , ISSN: 0277-786X
The results of a marine trial for a cold atom system for inertial navigation (HARLEQUIN) is presented. The system is a deployable atom interferometer demonstrator for navigation using inertial measurements. The interferometer is a grating based, Mach-Zehnder interferometer using rubidium-87 to make measurements of acceleration in a single axis. The output of the quantum sensor is used to condition classical sensors, in a quantum-classical hybrid measurement scheme. The subsystems of HARLEQUIN have been tested aboard a marine platform operated by the UK General Lighthouse Authority, to determine its performance in marine environments and informing an upgrade path to a fully deployable quantum sensor. Presented are results from the trial and upgrade path towards a fully deployable quantum sensor.
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Journal articleVylegzhanin A, Brown DJ, Abdrakhmanov S, et al., 2026, , Physical Review A, Vol: 113, ISSN: 2469-9926
<jats:p> We present a magnetic trapping scheme for cold <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mmultiscripts> <a:mi>Rb</a:mi> <a:mprescripts/> <a:none/> <a:mn>87</a:mn> </a:mmultiscripts> </a:math> atoms based on light-induced fictitious magnetic fields generated by the evanescent field of an optical nanofiber (ONF) integrated with optical tweezers. We calculate and compare the trapping potentials for both Gaussian and Laguerre-Gaussian modes of the tweezer beam, combined with a quasilinearly polarized ONF-guided field. Based on the optical powers in the tweezer and ONF modes, we analyze the trap depths and the positions of the potential minima from the nanofiber surface. We show that, by varying the optical powers in the two fields, the trap position can be tuned over several hundred nanometers while simultaneously influencing the trap depth and trap frequencies. Such control over the atom-surface position is essential for studying distance-dependent effects on atoms trapped near a dielectric surface and optimizing atom-photon interfaces for quantum technology applications. </jats:p>
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Journal articleGwak G, Roh C, Yoon Y-D, et al., 2026, , Nature Photonics, Vol: 20, Pages: 156-162, ISSN: 1749-4885
Complete characterization of a multimode optical process has paved the way for understanding complex optical phenomena, leading to the development of novel optical technologies. Until now, however, characterizations have mainly focused on linear optical processes, despite the importance of nonlinear optical processes for photonic technologies. Here we report the complete experimental characterization of multimode second-order nonlinear optical quantum processes—also known as bosonic Gaussian channels. Our resource-efficient characterization method, demonstrated on a 16-mode quantum process, captures the full information of non-unitary quantum evolution and satisfies the required physical condition. This complete characterization enables the identification of eigenquadratures and their associated amplification and noise properties. Moreover, we demonstrate the broad applicability of our method by characterizing various nonlinear optical quantum processes, including cluster-state generation, mode-dependent loss with nonlinear interaction and a quantum noise channel. Our method, by providing a versatile and efficient technique for characterizing a nonlinear optical process, will be beneficial for developing scalable photonic technologies.
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Journal articleGosling JMH, Pontin A, Alder F, et al., 2026, , Rev Sci Instrum, Vol: 97
Levitated optical mechanical systems have demonstrated excellent force and impulse sensitivity and are currently being developed for the creation of non-classical states of motion in these new quantum systems. An important requirement in the design of these systems is the ability to independently control and cool all three translational degrees of freedom. Here, we describe the design and implementation of a stable and robust 3D velocity feedback cooling scheme with particular emphasis on creating minimal crosstalk between the independent oscillatory modes when cooling.
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Journal articleKim M, Sun J, 2026, , Science Advances, Vol: 12, ISSN: 2375-2548
Estimating the eigenstate properties of quantum systems is a long-standing, challenging problem for both classical and quantum computing. Existing universal quantum algorithms typically rely on ideal and efficient query models (e.g. time evolution operator or block encoding of the Hamiltonian), which, however, become suboptimal for actual implementation at the quantum circuit level. Here, we present a full-stack design of quantum algorithms for estimating the eigenenergy and eigenstate properties, which can achieve high precision and good scaling with system size. The gate complexity per circuit for estimating generic Hamiltonians’ eigenstate properties is O(˜ log 饾満¯¹), which has a logarithmic dependence on the inverse precision 饾満. For lattice Hamiltonians, the circuit depth of our design achieves near-optimal system-size scaling, even with local qubit connectivity. Our full-stack algorithm has low overhead in circuit compilation, which thus results in a small actual gate count (cnot and non-Clifford gates) for lattice and molecular problems compared to advanced eigenstate algorithms. The algorithm is implemented on IBM quantum devices using up to 2,000 two-qubit gates and 20,000 single-qubit gates, and achieves high-precision eigenenergy estimation for Heisenberg-type Hamiltonians, demonstrating its noise robustness.
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Journal articleLee J, Omkar S, Teo YS, et al., 2025, , Newton, ISSN: 2950-6360
Photons are a ubiquitous carrier of quantum information: they are fast, suffer minimal decoherence, and do not require huge cryogenic facilities. Nevertheless, their intrinsically weak photon-photon interactions remain a key obstacle to scalable quantum computing. This review surveys hybrid photonic quantum computing, which exploits multiple photonic degrees of freedom to combine the complementary strengths of discrete and bosonic encodings, thereby significantly mitigating the challenge of weak photon-photon interactions. We first outline the basic principles of discrete-variable, native continuous-variable, and bosonic-encoding paradigms. We then summarize recent theoretical advances and state-of-the-art experimental demonstrations with a particular emphasis on the hybrid approach. Its unique advantages, such as efficient generation of resource states and nearly ballistic (active-feedforward-free) operations, are highlighted alongside the remaining technical challenges. To facilitate a clear comparison, we explicitly present the error thresholds and resource overheads required for fault-tolerant quantum computing. Our work offers a focused overview that clarifies how the hybrid approach enables scalable and compatible architectures for quantum computing.
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Journal articlePadilla-Castillo JE, Cai J, Agarwal P, et al., 2025, , PHYSICAL REVIEW LETTERS, Vol: 135, ISSN: 0031-9007
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Journal articleSireesh A, Alhajri A, Kim MS, et al., 2025, , Quantum Science and Technology, Vol: 10, ISSN: 2058-9565
Entangled quantum states are highly sensitive to noise, which makes it difficult to transfer them over noisy quantum channels or to store them in quantum memory. Here, we propose the disentangling quantum autoencoder (DQAE) to encode entangled states into single-qubit product states. The DQAE provides an exponential improvement in the number of copies needed to transport entangled states across qubit-loss or leakage channels compared to unencoded states. The DQAE can be trained in an unsupervised manner from entangled quantum data. For general states, we train via variational quantum algorithms based on gradient descent with purity-based cost functions, while stabilizer states can be trained via a Metropolis algorithm. For particular classes of states, the number of training data needed to generalize is surprisingly low: for stabilizer states, DQAE generalizes by learning from a number of training data that scales linearly with the number of qubits, while only 1 training sample is sufficient for states evolved with the transverse-field Ising Hamiltonian. Our work provides practical applications for enhancing near-term quantum computers.
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Journal articleAthanasakis M, Peng G, Li S, et al., 2025, , Physical Review Research, Vol: 7, ISSN: 2643-1564
We report radiation pressure slowing of YbF molecules to low velocity. In YbF, laser slowing is hindered by leaks out of the optical cycle attributed to low-lying metastable electronic states arising from inner-shell excitation. We bring this population back into the optical cycle once it has decayed to the electronic ground state using microwaves to couple the relevant rotational levels. We measure the scattering rate and closure of the optical cycle as repumps are added, and study the destabilzation of dark states by a magnetic field and by polarization modulation, finding that both are helpful for maximizing the scattering rate. Starting from a beam with a mean speed of 80 m/s, and using frequency broadened slowing light, we reduce the mean speed of the beam and produce a substantial flux in the low velocity tail of the distribution. Slowing increases the fraction of molecules below 40 m/s from 0.4(1)% to 7.0(2)%, and the fraction below 30 m/s from zero to 3.2(1)%. The establishment of a nearly-closed optical cycle and the production of molecules at low velocity are important steps towards trapping YbF molecules for future measurements of the electron’s electric dipole moment.
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Journal articleAlwehaibi Y, Mer E, Jimenez Machado G, et al., 2025, , Physical Review Research, Vol: 7, ISSN: 2643-1564
Certifying genuine nonclassical correlations over long distances is essential for device-independent quantum information. In photonic platforms, however, this remains challenging due to photon loss, which opens the detection loophole, rendering violations increasingly difficult for less-efficient detectors. Eberhard showed that using nonmaximally entangled states lowers the detection-efficiency threshold to 66.7%, but existing photonic approaches are restricted to short distances with linear transmittance scaling. Conversely, single-photon event-ready schemes extend the distance with favorable square-root scaling with channel transmittance, yet still demand detection efficiencies above 82.6%. Here, we propose the first all-photonic, heralded entanglement distribution protocol that unifies these two advances: It achieves a postselection-free violation at the Eberhard limit while preserving twin-field-like scaling. We identify the loss independent of the vacuum component amplitude of the prepared state as the source of this enhancement. Our approach addresses both resilience to loss and scalability, providing a practical route toward long-distance, loophole-free Bell tests and device-independent applications with current technology.
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Journal articleDewes BT, Klee T, Cottam ND, et al., 2025, , LIGHT-SCIENCE & APPLICATIONS, Vol: 14, ISSN: 2095-5545
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Journal articleKlee T, Broughton JJ, Tisch JWG, 2025, , OPTICS EXPRESS, Vol: 33, ISSN: 1094-4087
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Journal articleMartirosyan G, Gazo M, Etrych J, et al., 2025, , NATURE, ISSN: 0028-0836
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Journal articleCrescimanna V, Yu S, Heshami K, et al., 2025, , PHYSICAL REVIEW A, Vol: 112, ISSN: 2469-9926
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Journal articleCollings FJ, Fitch NJ, Jenkins RA, et al., 2025, , NEW JOURNAL OF PHYSICS, Vol: 27, ISSN: 1367-2630
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Journal articleXiong P, Ho KKK, Gosling JMH, et al., 2025, , Physical Review Research, Vol: 7, ISSN: 2643-1564
We study theoretically the creation of an optical centrifuge for the controlled rotation of levitated nanorotors within an optical tweezer. The optical centrifuge's motion is simulated by rapidly rotating the linear polarization of the tightly focused optical field used to form an optical trap. We show that nanorotors, formed by anisotropic nanoparticles levitated within a trap, can be accelerated to well-defined rotational rates in excess of 100 MHz over durations of hundreds of microseconds. The initial conditions required for stable acceleration, based on optical trap properties and the anisotropic susceptibility of the nanorotor are established and confirmed by numerical simulations. We also present initial experiments that have developed tools for the rapid angular acceleration of the polarization vector of the linearly polarized beam that is required to create the centrifuge. We show that over acceleration durations in the 100μs range, high rotational speeds could be achieved in modest vacuum.
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Journal articlePadilla-Castillo JE, Hofsass S, Palanki L, et al., 2025, , NATURAL SCIENCES, ISSN: 2698-6248
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Journal articleCheng MH, Chen Y-C, Wang Q, et al., 2025, , Physical Review Research, Vol: 7, ISSN: 2643-1564
Number-conserved subspace encoding reduces resources needed for quantum simulations, but scalable com plexity trade-off bounds for M modes and N particles with O(N log M) qubits have remained unknown. We studyqubit-gate-measurement trade-offs through the lens of classical/quantum error correction complexity and developa framework of fermionic gate and measurement complexity based on classical encoder/decoder appearing inthe error correction framework. We demonstrate optimal encoding with random classical parity check code andpropose the Fermionic Expectation Decoder for scalable probability decoding in O(M4 ) bases. The protocol istested with variational quantum eigensolver on LiH in the STO-3G and 6-31G bases, and H2 potential energycurve in the 6-311G* basis.
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Journal articlePatch MM, McClish R, Panchagnula S, et al., 2025, , Journal of the American Chemical Society, Vol: 147, Pages: 34508-34516, ISSN: 0002-7863
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Journal articleMa Y, Hanks M, Gneusheva E, et al., 2025,
Reshaping quantum device noise via repetition code circuits
, Physical Review Research, ISSN: 2643-1564Noise of a quantum processor can be an important resource for simulating open quantum dynamics. However, this requires characterizing the device noise and then transforming it into a target structure. Here we take the first step towards this goal: We analytically and numerically study re-shaping the noise associated with native trapped-ion two-qubit entangling gates via quantum circuits based on repetition codes, and demonstrate our findings on the IonQ Aria-1 quantum hardware. We investigate all the building blocks, including the quantum channels describing noisy two-qubit entangling gates, the compilation of the encoding circuits into native gates, and the propagation of two-qubit errors across ideal single-qubit gates
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Journal articleManceau M, Wall TE, Philip H, et al., 2025, , LASER & PHOTONICS REVIEWS, ISSN: 1863-8880
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Journal articlePeng G, Lanigan B, Shah R, et al., 2025, , Physical Review Research, Vol: 7, ISSN: 2643-1564
We present a Raman atom interferometer using large momentum transfer without reversing thedirection of the effective wavevector (k-reversal). More specifically, we use a microwave π/2 pulseto manipulate the spin state of 鈦糕伔Rb atoms before applying a Raman light π pulse to achieve 4鈩弅 momentum transfer per Raman light pulse. A microwave π pulse in the middle of the interferometer sequence reverses the spin states, which allows closing of the interferometer arms by the same Raman light π pulses without propagation reversal. We present a proof-of-principle demonstration of a 4鈩弅large-momentum-transfer (LMT) atom interferometer and discuss its scalability. Our results extend the scope of using LMT atom optics.
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Journal articleBroughton JJ, Allegre H, Klee T, et al., 2025, , Applied Optics, Vol: 64, Pages: 7060-7064, ISSN: 1559-128X
Controlling the intensity of few-cycle laser pulses—often with fine and continuous tunability—is essential forapplications ranging from strong-field physics and attosecond science to ultrafast spectroscopy, nonlinear optics, and precision material processing. Yet this remains challenging due to their octave-spanning bandwidth and high sensitivity to dispersion. Conventional polarization-based methods typically rely on ultrabroadband optics, which are complex and costly. We demonstrate a robust and broadly applicable approach that enables precise intensity control while avoiding these demanding optical requirements. Applied to an ∼800 nm laser, the method allows pulse energy tuning over a factor of ∼25 while maintaining a sub-6 fs pulse duration after post compression in an argon-filled hollow fiber and chirped mirror system. Validation through high-harmonic generation in krypton reveals clear intensity-dependent harmonic yields across 30−190 TW/cm². This work provides a practical and effective route to stable, tunable few-cycle pulses for both experimental and applied settings.
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