Publications

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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Citations: 1

Journal article

Padilla-Castillo JE, Hofsass S, Palanki L, Cai J, Rich CJH, Thomas R, Kray S, Meijer G, Wright SC, Truppe Set al., 2025,

A Large Magneto-Optical Trap of Cadmium Atoms Loaded From a Cryogenic Buffer Gas Beam

, NATURAL SCIENCES, ISSN: 2698-6248

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Journal article

Cheng MH, Chen Y-C, Wang Q, Bartsch V, Medina AC, Kim MS, Hu A, Hsieh M-Het al., 2025,

Optimal number-conserved linear encoding for practical fermionic simulation

, 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.

Journal article

Patch MM, McClish R, Panchagnula S, Rap DB, Banhatti S, Hrodmarsson HR, Brünken S, Linnartz H, Tielens AGGM, Bouwman Jet al., 2025,

Radical Isomerization upon Dissociative Electron Ionization of Anthracene and Phenanthrene

, Journal of the American Chemical Society, Vol: 147, Pages: 34508-34516, ISSN: 0002-7863

Journal article

Manceau M, Wall TE, Philip H, Baranov A, Lopez O, Tarbutt MR, Teissier R, Darquie Bet al., 2025,

Demonstration and Frequency Noise Characterization of a 17 μm Quantum Cascade Laser

, LASER & PHOTONICS REVIEWS, ISSN: 1863-8880

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Journal article

Ma Y, Hanks M, Gneusheva E, Kim MSet al., 2025,

Reshaping quantum device noise via repetition code circuits

, Physical Review Research, Vol: 7, ISSN: 2643-1564

Noise 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.

Journal article

Peng G, Lanigan B, Shah R, Lim J, Kaushik A, Cotter J, Hinds E, Sauer Bet al., 2025,

Large momentum transfer Raman atom interferometer without 𝑘-reversal

, 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 ⁸⁷Rb atoms before applying a Raman light π pulse to achieve 4ℏk 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 4ℏklarge-momentum-transfer (LMT) atom interferometer and discuss its scalability. Our results extend the scope of using LMT atom optics.

Journal article

Broughton JJ, Allegre H, Klee T, Li Y, Lim D, Thatte N, Matthews MM, Tisch JWGet al., 2025,

Intensity control of few-cycle laser pulses

, 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.

Journal article

Li Y, Broughton JJ, Tisch JWG, 2025,

Temporal compression of Yb-doped laser pulses in cascaded gas-filled hollow fibers

, OPTICS CONTINUUM, Vol: 4, Pages: 1732-1743

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Journal article

Latacz BM, Erlewein SR, Fleck M, Jager JI, Abbass F, Arndt BP, Geissler P, Imamura T, Leonhardt M, Micke P, Mooser A, Schweitzer D, Voelksen F, Wursten E, Yildiz H, Blaum K, Devlin JA, Matsuda Y, Ospelkaus C, Quint W, Soter A, Walz J, Yamazaki Y, Smorra C, Ulmer Set al., 2025,

Coherent spectroscopy with a single antiproton spin

, Nature, Vol: 644, Pages: 64-68, ISSN: 0028-0836

Coherent quantum transition spectroscopy is a powerful tool in metrology¹, quantum information processing², magnetometry³, and precision tests of the Standard Model⁴. It was applied with great success in proton and deuteron magnetic moment measurements⁵, which culminated in MASER spectroscopy with sub-parts per trillion resolution⁶ and many other experiments at the forefront of physics⁷. All these experiments were performed on macroscopic ensembles of particles, while the coherent spectroscopy of a “free” single nuclear spin has never been reported before. Here, we demonstrate coherent quantum transition spectroscopy of the spin of a single antiproton stored in a cryogenic Penning-trap system. We apply a multi-trap technique⁸, detect the antiproton spin-state using the continuous Stern-Gerlach-effect⁹, and transport the particle to the homogeneous magnetic field of a precision trap (PT). Here, we induce the coherent dynamics and analyze the result by quantum-projection measurements in the analysis trap¹⁰ . We observe for the first time Rabi-oscillations of an antiproton spin and achieve in time-series measurements spin inversion probabilities above 80% at spin coherence times of ≈ 50s. Scans of single-particle spin resonances show inversions >70%, at transition line-widths 16 times narrower than in previous measurements⁸, limited by cyclotron frequency measurement decoherence. This achievement marks a major step towards at least 10-fold improved tests of matter/antimatter symmetry using proton and antiproton magnetic moments.

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Journal article

Haug T, Aolita L, Kim MS, 2025,

Probing quantum complexity via universal saturation of stabilizer entropies

, Quantum, Vol: 9, Pages: 1801-1801, ISSN: 2521-327X

Nonstabilizerness or `magic' is a key resource for quantum computing and a necessary condition for quantum advantage. Non-Clifford operations turn stabilizer states into resourceful states, where the amount of nonstabilizerness is quantified by resource measures such as stabilizer Rényi entropies (SREs). Here, we show that SREs saturate their maximum value at a critical number of non-Clifford operations. Close to the critical point SREs show universal behavior. Remarkably, the derivative of the SRE crosses at the same point independent of the number of qubits and can be rescaled onto a single curve. We find that the critical point depends non-trivially on Rényi index α. For random Clifford circuits doped with T-gates, the critical T-gate density scales independently of α. In contrast, for random Hamiltonian evolution, the critical time scales linearly with qubit number for α>1, while it is a constant for α<1. This highlights that α-SREs reveal fundamentally different aspects of nonstabilizerness depending on α: α-SREs with α<1 relate to Clifford simulation complexity, while α>1 probe the distance to the closest stabilizer state and approximate state certification cost via Pauli measurements. As technical contributions, we observe that the Pauli spectrum of random evolution can be approximated by two highly concentrated peaks which allows us to compute its SRE. Further, we introduce a class of random evolution that can be expressed as random Clifford circuits and rotations, where we provide its exact SRE. Our results opens up new approaches to characterize the complexity of quantum systems.

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Journal article

Li Z, Solomons NR, Bulmer JFF, Patel RB, Walmsley IAet al., 2025,

A complexity transition in displaced Gaussian Boson sampling

, npj Quantum Information, Vol: 11, ISSN: 2056-6387

Gaussian Boson Sampling (GBS) is the problem of sampling from the output of photon-number-resolving measurements of squeezed states input to a linear optical interferometer. For purposes of demonstrating quantum computational advantage as well as practical applications,a large photon number is often desirable. However, producing squeezed states with high photon numbers is experimentally challenging. In this work, we examine the computational complexity implications of increasing the photon number by introducing coherent states. This displaces the state in phase space and as such we call this modified problem Displaced GBS. By utilising a connection to the matching polynomial in graph theory, we first describe an efficient classical algorithm for Displaced GBS when displacement is high or when the output state is represented by a non-negative graph. Then we provide complexity theoretic arguments for the quantum advantage of the problem in the low-displacement regime and numerically quantify where the complexity transition occurs.

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Journal article

Vylegzhanin A, Brown DJ, Kornovan DF, Brion E, Chormaic SNet al., 2025,

Towards a fictitious magnetic field trap for both ground and Rydberg state <SUP>87</SUP>Rb atoms via the evanescent field of an optical nanofiber

, NEW JOURNAL OF PHYSICS, Vol: 27, ISSN: 1367-2630

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Journal article

Bressanini G, Seron B, Novo L, Cerf NJ, Kim MSet al., 2025,

Binned-detector probability distributions for Gaussian boson sampling validation

, Physical Review A: Atomic, Molecular and Optical Physics, Vol: 112, ISSN: 1050-2947

Gaussian boson sampling (GBS), a computational problem conjectured to be hard to simulate on a classical machine, has been at the forefront of recent years' experimental and theoretical efforts to demonstrate quantum advantage. The classical intractability of the sampling task makes validating these experiments a challenging and essential undertaking. In this paper, we propose binned-detector probability distributions as a suitable quantity to statistically validate GBS experiments employing photon-number-resolving detectors. We develop the theoretical framework to compute such distributions by leveraging their connection with their respective characteristic function. The latter may be efficiently and analytically computed for squeezed input states as well as for relevant classical hypothesis like squashed states. Our theoretical framework encompasses other validation methods based on marginal distributions and correlation functions. Additionally, it can analytically accommodate various sources of noise, such as losses and partial distinguishability, a feature that has received limited attention within the GBS framework so far. We also derive how binned-detector probability distributions behave when Haar averaged over all possible interferometric networks, extending known results for Fock boson sampling.

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Journal article

Li Z, Kendall MJH, Machado GJ, Zhu R, Mer E, Zhan H, Zhang A, Yu S, Walmsley IA, Patel RBet al., 2025,

Boosting photon-number-resolved detection rates of transition-edge sensors by machine learning

, Optica Quantum, Vol: 3, Pages: 246-246, ISSN: 2837-6714

Transition-edge sensors (TESs) are very effective photon-number-resolving (PNR) detectors that have enabled many photonic quantum technologies. However, their relatively slow thermal recovery time severely limits their operation rate in experimental scenarios compared with leading non-PNR detectors. In this work, we develop an algorithmic approach that enables TESs to detect and accurately classify photon pulses without waiting for a full recovery time between detection events. We propose two machine-learning-based signal processing methods: one supervised learning method and one unsupervised clustering method. By benchmarking against data obtained using coherent states and squeezed states, we show that the methods extend the TES operation rate to 800 kHz, achieving at least a four-fold improvement, whilst maintaining accurate photon-number assignment up to at least five photons. Our algorithms will find utility in applications where high rates of PNR detection are required and in technologies that demand fast active feed-forward of PNR detection outcomes.

Journal article

Maslennikov DR, Maimaris M, Ning H, Zheng X, Mondal N, Bruevich VV, Pratik SM, Dong Y, Tisch JWG, Musser AJ, Podzorov V, Bredas J-L, Coropceanu V, Bakulin AAet al., 2025,

Interplay between Mixed and Pure Exciton States Controls Singlet Fission in Rubrene Single Crystals

, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 147, Pages: 23536-23544, ISSN: 0002-7863

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Journal article

Ho CJ, Fischer SM, Martirosyan G, Morris SJ, Etrych J, Eigen C, Hadzibabic Zet al., 2025,

Joule expansion of a quantum gas

, PHYSICAL REVIEW RESEARCH, Vol: 7

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Journal article

Cheng MH, Khosla KE, Self CN, Lin M, Li BX, Medina AC, Kim MSet al., 2025,

Clifford circuit initialization for variational quantum algorithms

, Physical Review A, Vol: 111, ISSN: 2469-9926

We present an initialization method for variational quantum algorithms applicable to intermediate-scale quantum computers. The method explores the efficiently classically simulable Clifford points of a parameterized quantum circuit, using simulated annealing to find a low-energy initial state. We provide numerical evidence of the effectiveness of the technique for different choices of the Hamiltonian structure, number of qubits, and circuit depth. While a number of problems are considered, we note that the method is particularly useful for quantum chemistry problems, for which it is able to capture long-range correlation energy. The presented method could help achieve a quantum advantage in noisy or fault-tolerant intermediate-scale devices by preparing a high-quality initial state.

Journal article

Etrych J, Martirosyan G, Cao A, Ho CJ, Hadzibabic Z, Eigen Cet al., 2025,

Universal Quantum Dynamics of Bose Polarons

, PHYSICAL REVIEW X, Vol: 15, ISSN: 2160-3308

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Citations: 6

Journal article

Leonhardt M, Schweitzer S, Abbass F, Anjum KK, Arndt B, Erlewein S, Endo S, Geissler P, Imamura T, Jager JI, Latacz BM, Micke P, Voelksen F, Yildiz H, Blaum K, Devlin J, Matsuda Y, Ospelkaus C, Quint W, Soter A, Walz J, Yamazaki Y, Ulmer S, Smorra Cet al., 2025,

Proton transport from the antimatter factory of CERN

, Nature, ISSN: 0028-0836

Precision measurements using low-energy antiprotons, exclusively available at the antimatter factory (AMF) of CERN1, offer stringent tests of charge–parity–time (CPT) invariance, which is a fundamental symmetry in the Standard Model of particle physics2. These tests have been realized, for example, in antiprotonic helium3 and antihydrogen4. In our cryogenic Penning-trap experiments5, we measure the magnetic moments6,7 and charge-to-mass ratios of protons and antiprotons and now provide the most precise test of CPT invariance in the baryon sector8. Our experiments are limited by magnetic field fluctuations imposed by the decelerators in the AMF; therefore, we are advancing the relocation of antiprotons to dedicated precision laboratories. Here we present the successful transport of a trapped proton cloud from the AMF using BASE-STEP9—a transportable, superconducting, autonomous and open Penning-trap system that can distribute antiprotons into other experiments. We transferred the trapped protons from our experimental area at the AMF onto a truck and transported them across the Meyrin site of CERN, demonstrating autonomous operation without external power for 4 h and loss-free proton relocation. We thereby confirm the feasibility of transferring particles into low-noise laboratories in the vicinity of the AMF and of using a power generator on the truck10 to reach laboratories throughout Europe. This marks the potential start of a new era in precision antimatter research, enabling low-noise measurements of antiprotons, the charged antimatter ions H+11 and H-2 (ref. 12), and other accelerator-produced ions, such as hydrogen-like lead or uranium ions13,14.

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Journal article

Li H, Xie J, Kwon H, Zhao Y, Kim M, Zhang Let al., 2025,

Experimental demonstration of generalized quantum fluctuation theorems in the presence of coherence

, Science Advances, Vol: 11, ISSN: 2375-2548

Fluctuation theorems have elevated the second law of thermodynamics to a statistical realm by establishing a connection between time-forward and time-reversal probabilities, providing invaluable insight into nonequilibrium dynamics. While well established in classical systems, their quantum generalization, incorporating coherence and the diversity of quantum noise, remains open. We report the experimental validation of a quantum fluctuation theorem (QFT) in a photonic system, applicable to general quantum processes with nonclassical characteristics, including quasi-probabilistic descriptions of entropy production and multiple time-reversal processes. Our experiment confirms that the ratio between the quasi-probabilities of the time-forward and any multiple time-reversal processes obeys a generalized Crooks QFT. Moreover, coherence induced by a quantum process leads to the imaginary components of quantum entropy production, governing the phase factor in the QFT. These findings underscore the fundamental symmetry between a general quantum process and its time reversal, providing an elementary toolkit to explore noisy quantum information processing.

Journal article

Alexander O, Ayuso D, Matthews M, Rego L, Tisch JWG, Weaver B, Marangos JPet al., 2025,

Attosecond physics and technology

, APPLIED PHYSICS LETTERS, Vol: 126, ISSN: 0003-6951

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Citations: 1

Journal article

Morris SJ, Ho CJ, Fischer SM, Etrych J, Martirosyan G, Hadzibabic Z, Eigen Cet al., 2025,

Scaling laws governing the collapse of a Bose-Einstein condensate

, PHYSICAL REVIEW A, Vol: 111, ISSN: 2469-9926

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Citations: 1

Journal article

Abdalla A, Abe M, Abend S, Abidi M, Aidelsburger M, Alibabaei A, Allard B, Antoniadis J, Arduini G, Augst N, Balamatsias P, Balaž A, Banks H, Barcklay RL, Barone M, Barsanti M, Bason MG, Bassi A, Bayle J-B, Baynham CFA, Beaufils Q, Beldjoudi S, Belić A, Bennetts S, Bernabeu J, Bertoldi A, Bigard C, Bigelow NP, Bingham R, Blas D, Bobrick A, Boehringer S, Bogojević A, Bongs K, Bortoletto D, Bouyer P, Brand C, Buchmueller O, Buica G, Calatroni S, Calmels L, Canizares P, Canuel B, Caramete A, Caramete L-I, Carlesso M, Carlton J, Carman SP, Carroll A, Casariego M, Chairetis M, Charmandaris V, Chauhan U, Chen J, Chiofalo MLM, Ciampini D, Cimbri A, Cladé P, Coleman J, Constantin FL, Contaldi CR, Corgier R, Dash B, Davies GJ, de Rham C, De Roeck A, Derr D, Dey S, Di Pumpo F, Djordjevic GS, Döbrich B, Dornan P, Doser M, Drougakis G, Dunningham J, Duspayev A, Easo S, Eby J, Efremov M, Elertas G, Ellis J, Entin N, Fairhurst S, Fanì M, Fassi F, Fayet P, Felea D, Feng J, Flack R, Foot C, Freegarde T, Fuchs E, Gaaloul N, Gao D, Gardner S, Garraway BM, GarridoAlzar CL, Gauguet A, Giese E, Gill P, Giudice GF, Glasbrenner EP, Glick J, Graham PW, Granados E, Griffin PF, Gué J, Guellati-Khelifa S, Gupta S, Gupta V, Hackermueller L, Haehnelt M, Hakulinen T, Hammerer K, Hanımeli ET, Harte T, Hartmann S, Hawkins L, Hees A, Herbst A, Hird TM, Hobson R, Hogan J, Holst B, Holynski M, Hosten O, Hsu CC, Huang WC-W, Hughes KM, Hussain K, Hütsi G, Iovino A, Isfan M-C, Janson G, Jeglič P, Jetzer P, Jiang Y, Juzeliūnas G, Kaenders W, Kalliokoski M, Kehagias A, Kilian E, Klempt C, Knight P, Koley S, Konrad B, Kovachy T, Krutzik M, Kumar M, Kumar P, Labiad H, Lan S-Y, Landragin A, Landsberg G, Langlois M, Lanigan B, Leone B, Le Poncin-Lafitte C, Lellouch S, Lewicki M, Lien Y-H, Lombriser L, Asamar EL, Lopez-Gonzalez JL, Lu C, Luciano GG, Lundblad N, de JLópezMonjaraz C, Lowe A, Mackoit-Sinkevičienė M, Maggiore M, Majumdar A, Makris K, Maleknejad A, Marchant AL, Mariotti A, Markou C, Matthews Bet al., 2025,

Terrestrial Very-Long-Baseline Atom Interferometry: summary of the second workshop

, EPJ Quantum Technology, Vol: 12, ISSN: 2196-0763

This summary of the second Terrestrial Very-Long-Baseline Atom Interferometry (TVLBAI) Workshop provides a comprehensive overview of our meeting held in London in April 2024 (Second Terrestrial Very-Long-Baseline Atom Interferometry Workshop, Imperial College, April 2024), building on the initial discussions during the inaugural workshop held at CERN in March 2023 (First Terrestrial Very-Long-Baseline Atom Interferometry Workshop, CERN, March 2023). Like the summary of the first workshop (Abend et al. in AVS Quantum Sci. 6:024701, 2024), this document records a critical milestone for the international atom interferometry community. It documents our concerted efforts to evaluate progress, address emerging challenges, and refine strategic directions for future large-scale atom interferometry projects. Our commitment to collaboration is manifested by the integration of diverse expertise and the coordination of international resources, all aimed at advancing the frontiers of atom interferometry physics and technology, as set out in a Memorandum of Understanding signed by over 50 institutions (Memorandum of Understanding for the Terrestrial Very Long Baseline Atom Interferometer Study).

Journal article

Thielemann F, Siemund J, von Schoenfeld D, Wu W, Weckesser P, Jachymski K, Walker T, Schaetz Tet al., 2025,

Exploring Atom-Ion Feshbach Resonances below the s-Wave Limit

, PHYSICAL REVIEW X, Vol: 15, ISSN: 2160-3308

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Citations: 4

Journal article

Athanasakis-Kaklamanakis M, Wilkins SG, Skripnikov LV, Koszorus A, Breier AA, Ahmad O, Au M, Bai SW, Belosevic I, Berbalk J, Berger R, Bernerd C, Bissell ML, Borschevsky A, Brinson A, Chrysalidis K, Cocolios TE, de Groote RP, Dorne A, Fajardo-Zambrano CM, Field RW, Flanagan KT, Franchoo S, Garcia Ruiz RF, Gaul K, Geldhof S, Giesen TF, Hanstorp D, Heinke R, Imgram P, Isaev TA, Kyuberis AA, Kujanpaa S, Lalanne L, Lassegues P, Lim J, Liu YC, Lynch KM, Mcglone A, Mei WC, Neyens G, Nichols M, Nies L, Pasteka LF, Perrett HA, Raggio A, Reilly JR, Rothe S, Smets E, Udrescu S-M, van den Borne B, Wang Q, Warbinek J, Wessolek J, Yang XF, Zulch Cet al., 2025,

Electron correlation and relativistic effects in the excited states of radium monofluoride

, NATURE COMMUNICATIONS, Vol: 16

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Citations: 4

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