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  • 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
  • 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
    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
  • Journal article
    Allegre H, Broughton JJ, Klee T, Li Y, Kowalczyk KM, Thatte N, Lim D, Marangos JP, Matthews MM, Tisch JWGet al., 2025,

    Extension of high-harmonic generation cutoff in solids to 50 eV using MgO

    , OPTICS LETTERS, Vol: 50, Pages: 1492-1495, ISSN: 0146-9592
  • Journal article
    Klee T, Mukherjee R, Broughton JJ, Ferchaud C, Brahms C, Travers JC, Mintert F, Tisch JWGet al., 2025,

    Bayesian optimization of resonant dispersive wave generation in hollow capillary fibers

    , Optics Express, Vol: 33, ISSN: 1094-4087

    Resonant dispersive wave (RDW) generation in hollow capillary fibers (HCFs) is a powerful technique for producing ultrashort light pulses in the deep ultraviolet range, which are important for ultrafast spectroscopy and material processing. However, the complex nonlinear dynamics governing this process and the large associated parameter space make it challenging to achieve optimal RDW pulses with the highest peak power. In this study, Bayesian optimization (BO) is coupled with the open source Luna.jl simulation framework to optimize the HCF and pump pulse paramters for less than 5 femtosecond (fs) RDW generation at a target wavelength of 200 nm. Temporally non-structured RDW were consistently identified with peak powers of up to 14 GW, exceeding experimentally published values by up to 70 %. Furthermore, a subset of the RDW optima exhibited an energy stability that is better than that of the pump pulse. Given that this approach can be generalized to other RDW wavelengths, our findings suggest that BO is a valuable tool in developing HCF systems that support RDW generation tailored to a particular experimental need.
  • Journal article
    Cryer-Jenkins EA, Major KD, Clarke J, Enzian G, Szczykulska M, Zhang J, Gupta A, Leung AC, Rathee H, Svela AO, Tan AKC, Beige A, Molmer K, Vanner MRet al., 2025,

    Enhanced Laser Cooling of a Mechanical Resonator via Zero-Photon Detection

    , PHYSICAL REVIEW LETTERS, Vol: 134, ISSN: 0031-9007
  • Journal article
    Clarke J, Cryer-Jenkins EA, Gupta A, Major KD, Zhang J, Enzian G, Szczykulska M, Leung AC, Rathee H, Svela AO, Tan AKC, Beige A, Molmer K, Vanner MRet al., 2025,

    Theoretical framework for enhancing or enabling cooling of a mechanical resonator via the anti-Stokes or Stokes interaction and zero-photon detection

    , PHYSICAL REVIEW A, Vol: 111, ISSN: 2469-9926
  • Journal article
    Sun J, Vilchez-Estevez L, Vedral V, Boothroyd AT, Kim MSet al., 2025,

    Probing spectral features of quantum many-body systems with quantum simulators

    , NATURE COMMUNICATIONS, Vol: 16
  • Journal article
    Wang Y, Rodewald J, Lopez O, Manceau M, Darquie B, Sauer BE, Tarbutt MRet al., 2025,

    Wavelength modulation laser spectroscopy of N<sub>2</sub>O at 17 <i>μ</i>m

    , NEW JOURNAL OF PHYSICS, Vol: 27, ISSN: 1367-2630
  • Journal article
    Wang J, Driver T, Franz PL, Kolorenc P, Thierstein E, Robles RR, Isele E, Guo Z, Cesar D, Alexander O, Beauvarlet S, Borne K, Cheng X, DiMauro LF, Duris J, Glownia JM, Grassl M, Hockett P, Hoffman M, Kamalov A, Larsen KA, Li S, Li X, Lin M-F, Obaid R, Rosenberger P, Walter P, Wolf TJA, Marangos JP, Kling MF, Bucksbaum PH, Marinelli A, Cryan JPet al., 2025,

    Probing Electronic Coherence between Core-Level Vacancies at Different Atomic Sites

    , PHYSICAL REVIEW X, Vol: 15, ISSN: 2160-3308
  • Journal article
    Wang P, Kwon H, Luan C-Y, Chen W, Qiao M, Zhou Z, Wang K, Kim MS, Kim Ket al., 2025,

    Snapshotting quantum dynamics at multiple time points (vol 15, 8900, 2024)

    , NATURE COMMUNICATIONS, Vol: 16
  • Journal article
    Cryer-Jenkins E, Leung A, Rathee H, Tan A, Major K, Vanner Met al., 2025,

    Brillouin-Mandelstam scattering in telecommunications optical fiber at millikelvin temperatures

    , APL Photonics, Vol: 10, ISSN: 2378-0967

    Brillouin–Mandelstam scattering is a strong and readily accessible optical nonlinearity, enabling a wide array of applications and research directions. For instance, the three-wave mixing process has been employed to great success in narrow-linewidth lasers, sensing applications, microscopy, and signal processing. While most of these avenues focus on room temperature operation, there is now increasing interest in cryogenic operation owing to the scattering mechanism’s significant potential for applications and fundamental physics at low temperatures. Here, we measure the Brillouin scattering spectrum in standard single-mode telecommunication optical fibers at millikelvin temperatures using a closed-cycle dilution refrigerator and optical heterodyne detection. Our experiments are performed with a cryostat temperature from 50 mK to 27 K, extending previously reported measurements that utilized liquid helium-4 cryostats with temperatures greater than 1 K. At millikelvin temperatures, our experiment observes coherent acoustic interactions with microscopic defects in the amorphous material—two-level-systems (TLSs)—which has not been previously observed in optical fibers. The measured behavior of the linewidth with temperature is in agreement with the well-established models of ultrasonic attenuation in amorphous materials comprising a background intrinsic scattering, thermally activated scattering, and incoherent and coherent TLS interactions. This work provides a foundation for a wide range of applications and further research, including sensing applications, new approaches to investigate TLS physics, and Brillouin-scattering-based quantum science and technology.
  • Conference paper
    Rowley M, Webber-Date A, Osborn PF, Shah R, Krastev T, Cannon R, Griffin P, Riis E, Cotter J, Burrow O, Boughton Eet al., 2025,

    A Quantum-classical cold atom system for inertial navigation

    Global positioning and navigation using satellites has been a crucial part of modern infrastructure since the development of GPS in the 1970s, providing a positioning uncertainty less than 5 meters. However, such signals cannot be accessed underground or underwater and may be jammed or spoofed with relative ease. There remains, therefore, an important and practical need for precision navigation that does not rely on communication with an external source.
  • Conference paper
    White AD, Ainsworth A, Bahra D, Shah R, Sewell H, Kaushik A, Cotter JPet al., 2025,

    Quantum Sensing for Rail Positioning

    Global navigation satellite systems (GNSS) are critical to our daily lives and underpin numerous sectors including transport, finance, and defence. The estimated financial impact of GNSS failure for the UK is over £1bn per day [1]. In areas where GNSS cannot be used, inertial navigation provides an alternative to accurately position vehicles. For many applications, the drift in the classical accelerometers and gyroscopes that underpin inertial navigation systems limits the position accuracy that can be achieved.
  • Conference paper
    Vanner MR, 2025,

    Towards quantum science and technology with Brillouin-Mandelstam scattering

    , 2025 Conference on Quantum Sensing, Imaging, and Precision Metrology, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
  • Conference paper
    Webber-Date A, Rowley M, Osborn PF, Shah R, Krastev T, Cannon R, Griffin P, Riis E, Cotter J, Burrow O, Boughton Eet al., 2025,

    A quantum-classical cold atom system for inertial navigation

    , 2025 Conference on Quantum Sensing, Imaging, and Precision Metrology, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
  • Journal article
    Gerry CC, Birrittella RJ, Alsing PM, Mimih J, Knight PLet al., 2024,

    Non-classicality and the effect of one photon

    , PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 382, ISSN: 1364-503X
  • Journal article
    Orozco Ruiz M, Le NH, Mintert F, 2024,

    Quantum control without quantum states

    , PRX Quantum, ISSN: 2691-3399

    We show that combining ideas from the fields of quantum invariants and of optimal control can be used to design optimal quantum control solutions without explicit reference to quantum states. We describe how control problems for state preparation and the realization of propagators can be formulated in this approach, and we provide explicit control solutions for a spin chain with an extended Ising Hamiltonian. The states considered for state-preparation protocols include eigenstates of Hamiltonians with more than pairwise interactions, and these Hamiltonians are also used for the definition of target propagators. The cost of describing suitable time-evolving operators grows only quadratically with the system size, allowing us to construct explicit control solutions for up to 50 spins. While sub-exponential scaling is obtained only in special cases, we provide several examples that demonstrate favourable scaling beyond the extended Ising model.
  • Journal article
    White A, Popa S, Mellado Munoz J, Fitch N, Sauer B, Lim J, Tarbutt Met al., 2024,

    Slow molecular beams from a cryogenic buffer gas source

    , Physical Review Research, Vol: 6, ISSN: 2643-1564

    We study the properties of a cryogenic buffer gas source that uses a low temperature two-stage buffer gas cell to produce very slow beams of ytterbium monofluoride molecules. The molecules are produced by laser ablation inside the cell and extracted into a beam by a flow of cold helium. We measure the flux and velocity distribution of the beam as a function of ablation energy, helium flow rate, cell temperature, and the size of the gap between the first and second stages of the cell. We also compare the velocity distributions from one-stage and two-stage cells. The one-stage cell emits a beam with a speed of about 82 m s¯¹ and a translational temperature of 0.63 K. The slowest beams are obtained using the two-stage cell at the lowest achievable cell temperature of 1.8 K. This beam has a peak velocity of 56 m s¯¹ and a flux of 9×10⁹ ground state molecules per steradian per pulse, with a substantial fraction at speeds below 40 m s¯¹. These slow molecules can be decelerated further by radiation pressure slowing and then captured in a magneto-optical trap.
  • Journal article
    Ferte A, Austin D, Johnson AS, McGrath F, Malhado JP, Marangos JP, Vacher Met al., 2024,

    Signature of Attochemical Quantum Interference upon Ionization and Excitation of an Electronic Wave Packet in Fluorobenzene

    , PHYSICAL REVIEW LETTERS, Vol: 133, ISSN: 0031-9007
  • Journal article
    Vylegzhanin A, Chormaic SN, Brown DJ, 2024,

    Rydberg electromagnetically induced transparency based laser lock to Zeeman sublevels with 0.6 GHz scanning range

    , REVIEW OF SCIENTIFIC INSTRUMENTS, Vol: 95, ISSN: 0034-6748
  • Journal article
    Wang P, Kwon H, Luan C-Y, Chen W, Qiao M, Zhou Z, Wang K, Kim MS, Kim Ket al., 2024,

    Snapshotting quantum dynamics at multiple time points

    , NATURE COMMUNICATIONS, Vol: 15
  • Journal article
    Broughton JJ, Patra S, Parkes MA, Worth GA, Fielding HHet al., 2024,

    A multiphoton ionisation photoelectron imaging study of thiophene

    , PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 26, Pages: 25461-25468, ISSN: 1463-9076
  • Journal article
    Devlin J, 2024,

    Dark matter: what is it, and can quantum sensors help find it?

    , Contemporary Physics, Vol: 65, Pages: 239-258, ISSN: 0010-7514

    Dark matter is the name given to the unknown substance or substances which appears to make up 26.4⁢(6)% of the total mass-energy density of the Universe, making it 5 times more abundant than normal matter. Over 50 years of measurements have given us considerable evidence for the existence of dark matter and some of its properties. However, we still do not know, microscopically, what sort of stuff it is. In recent years, researchers have started to use techniques developed in quantum science to build experiments which are sensitive to certain types of dark matter. These techniques rely on the remarkable progress in isolating and measuring specific quantum systems, to such an extent that these experiments are now sensitive to the weak perturbations due to dark matter. This article gives an introduction to dark matter and efforts to search for it with quantum sensors.
  • Journal article
    Pitchford A, Rakhubovsky AA, Mukherjee R, Moore DW, Sauvage F, Burgarth D, Filip R, Mintert Fet al., 2024,

    Bayesian optimization of non-classical optomechanical correlations

    , QUANTUM SCIENCE AND TECHNOLOGY, Vol: 9, ISSN: 2058-9565
  • Journal article
    Ruberti M, Averbukh V, Mintert F, 2024,

    Bell test of quantum entanglement in attosecond photoionization

    , Physical Review X, Vol: 14, ISSN: 2160-3308

    Attosecond physics enables the study of ultrafast coherent electron dynamics in matter upon photoexcitation and photoionization, revealing spectacular effects such as hole migration and coherentAuger dynamics in molecules. In the photoionization scenario, there has been a strong focus onprobing the physical manifestations of internal quantum coherence within the individual parent ionand photoelectron systems. However, quantum correlations between these two subsystems emergingfrom attosecond photoionization events have thus far remained much more elusive. In this work, wedesign theoretically and model numerically a direct probe of quantum entanglement in attosecondphotoionization in the form of a Bell test. We simulate from first principles a Bell test protocolfor the case of noble gas atoms photoionized by ultrashort, circularly polarized infrared laser pulsesin the strong-field regime predicting robust violation of the Bell inequality. This theoretical resultpaves the way for the direct observation of entanglement in the context of ultrafast photoionizationof many-electron systems. Our work provides a novel perspective on attosecond physics directedtoward the detection of quantum correlations between systems born during attosecond photoionization and unraveling the signatures of entanglement in ultrafast coherent molecular dynamics,including in the chemical decomposition pathways of molecular ions.
  • Journal article
    Schofield RC, Fu M, Clarke E, Farrer I, Trapalis A, Dhar HS, Mukherjee R, Severs Millard T, Heffernan J, Mintert F, Nyman RA, Oulton RFet al., 2024,

    Bose–Einstein condensation of light in a semiconductor quantum well microcavity

    , Nature Photonics, Vol: 18, ISSN: 1749-4885

    When particles with integer spin accumulate at low temperature and high density, they undergo Bose–Einstein condensation (BEC). Atoms, magnons, solid-state excitons, surface plasmon polaritons and excitons coupled to light exhibit BEC, which results in high coherence due to massive occupation of the respective system’s ground state. Surprisingly, photons were shown to exhibit BEC recently in organic-dye-flled optical microcavities, which—owing to the photon’s low mass—occurs at room temperature. Here we demonstrate that photons within an inorganic semiconductor microcavity also thermalize and undergo BEC. Although semiconductor lasers are understood to operate out of thermal equilibrium, we identify a region of good thermalization in our system where we can clearly distinguish laser action from BEC. Semiconductor microcavities are a robust system for exploring the physics and applications of quantum statistical photon condensates. In practical terms, photon BECs ofer their critical behaviour at lower thresholds than lasers. Our study shows two further advantages: the lack of dark electronic states in inorganic semiconductors allows these BECs to be sustained continuously; and quantum wells ofer stronger photon–photon scattering. We measure an unoptimized interaction parameter ( g̃ ≳ 10–3), which is large enough to access the rich physics of interactions within BECs, such as superfuid light.
  • Journal article
    Yu S, Jia Z, Zhang A, Mer E, Li Z, Crescimanna V, Chen K-C, Patel RB, Walmsley IA, Kaszlikowski Det al., 2024,

    Shedding light on the future: exploring quantum neural networks through optics

    , Advanced Quantum Technologies, ISSN: 2511-9044

    At the dynamic nexus of artificial intelligence and quantum technology, quantum neural networks (QNNs) play an important role as an emerging technology in the rapidly developing field of quantum machine learning. This development is set to revolutionize the applications of quantum computing. This article reviews the concept of QNNs and their physical realizations, particularly implementations based on quantum optics. The integration of quantum principles with classical neural network architectures is first examined to create QNNs. Some specific examples, such as the quantum perceptron, quantum convolutional neural networks, and quantum Boltzmann machines are discussed. Subsequently, the feasibility of implementing QNNs through photonics is analyzed. The key challenge here lies in achieving the required non-linear gates, and measurement-induced approaches, among others, seem promising. To unlock the computational potential of QNNs, addressing the challenge of scaling their complexity through quantum optics is crucial. Progress in controlling quantum states of light is continuously advancing the field. Additionally, it has been discovered that different QNN architectures can be unified through non-Gaussian operations. This insight will aid in better understanding and developing more complex QNN circuits.
  • Journal article
    Lee JP, Avni T, Alexander O, Maimaris M, Ning H, Bakulin AA, Burden PG, Moutoulas E, Georgiadou DG, Brahms C, Travers JC, Marangos JP, Ferchaud Cet al., 2024,

    Few-femtosecond soft X-ray transient absorption spectroscopy with tuneable DUV-Vis pump pulses

    , Optica, Vol: 11, Pages: 1320-1323, ISSN: 2334-2536

    Achieving few-femtosecond resolution for a pump-probe experiment is crucial to measuring the fastest electron dynamics and for creating superpositions of valence states in quantum systems. However, traditional UV-Vis pump pulses cannot achieve few-fs durations and usually operate at fixed wavelengths. Here, we present, to our knowledge, an unprecedented temporal resolution and pump tuneability for UV-Vis-pumped soft X-ray transient absorption spectroscopy. We have combined few-fs deep-UV to visible tuneable pump pulses from resonant dispersive wave emission in hollow capillary fiber with attosecond soft X-ray probe pulses from high harmonic generation. We achieve sub-5-fs time resolution, sub-fs interferometric stability, and continuous tuneability of the pump pulses from 230 to 700 nm. We demonstrate that the pump can initiate an ultrafast photochemical reaction and that the dynamics at different atomic sites can be resolved simultaneously. These capabilities will allow studies of the fastest electronic dynamics in a large range of photochemical, photobiological and photovoltaic reactions.
  • Journal article
    Kilian E, Rademacher M, Gosling JMH, Iacoponi JH, Alder F, Toroš M, Pontin A, Ghag C, Bose S, Monteiro TS, Barker PFet al., 2024,

    Dark matter searches with levitated sensors

    , AVS Quantum Science, Vol: 6, ISSN: 2639-0213

    Motivated by the current interest in employing quantum sensors on Earth and in space to conduct searches for new physics, we provide a perspective on the suitability of large-mass levitated optomechanical systems for observing dark matter signatures. We discuss conservative approaches of recoil detection through spectral analysis of coherently scattered light, enhancements of directional effects due to cross-correlation spectral densities, and the possibility of using quantum superpositions of mesoscopic test particles to measure rare events.

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