Publications

Search or filter publications

Filter by type:

Filter by publication type

Filter by year:

to

Results

  • Showing results for:
  • Reset all filters

Search results

  • Journal article
    Tarrant J, Khokhlova M, Averbukh V, 2022,

    Publisher's Note: "Interferometry of quantum revivals" [J. Chem. Phys. 157, 054304 (2022)].

    , J Chem Phys, Vol: 157
  • Journal article
    Sempere-Llagostera S, Patel RB, Walmsley IA, Kolthammer WSet al., 2022,

    Experimentally Finding Dense Subgraphs Using a Time-Bin Encoded Gaussian Boson Sampling Device

    , PHYSICAL REVIEW X, Vol: 12, ISSN: 2160-3308
  • Journal article
    Zhang C, Tarbutt MR, 2022,

    Quantum Computation in a Hybrid Array of Molecules and Rydberg Atoms

    , PRX QUANTUM, Vol: 3
  • Journal article
    Völksen F, Devlin JA, Borchert MJ, Erlewein SR, Fleck M, Jäger JI, Latacz BM, Micke P, Nuschke P, Umbrazunas G, Wursten EJ, Abbass F, Bohman MA, Popper D, Wiesinger M, Will C, Blaum K, Matsuda Y, Mooser A, Ospelkaus C, Smorra C, Soter A, Quint W, Walz J, Yamazaki Y, Ulmer Set al., 2022,

    A high-Q superconducting toroidal medium frequency detection system with a capacitively adjustable frequency range >180 kHz.

    , Rev Sci Instrum, Vol: 93

    We describe a newly developed polytetrafluoroethylene/copper capacitor driven by a cryogenic piezoelectric slip-stick stage and demonstrate with the chosen layout cryogenic capacitance tuning of ≈60 pF at ≈10 pF background capacitance. Connected to a highly sensitive superconducting toroidal LC circuit, we demonstrate tuning of the resonant frequency between 345 and 685 kHz, at quality factors Q > 100 000. Connected to a cryogenic ultra low noise amplifier, a frequency tuning range between 520 and 710 kHz is reached, while quality factors Q > 86 000 are achieved. This new device can be used as a versatile image current detector in high-precision Penning-trap experiments or as an LC-circuit-based haloscope detector to search for the conversion of axion-like dark matter to radio-frequency photons. This new development increases the sensitive detection bandwidth of our axion haloscope by a factor of ≈1000.
  • Journal article
    Tarrant J, Khokhlova M, Averbukh V, 2022,

    Interferometry of quantum revivals

    , JOURNAL OF CHEMICAL PHYSICS, Vol: 157, ISSN: 0021-9606
  • Journal article
    Ruberti M, Patchkovskii S, Averbukh V, 2022,

    Quantum coherence in molecular photoionization

    , PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 24, Pages: 19673-19686, ISSN: 1463-9076
  • Journal article
    Frasinski LJ, 2022,

    Cumulant mapping as the basis of multi-dimensional spectrometry

    , PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 24, Pages: 20776-20787, ISSN: 1463-9076
  • Journal article
    Sun B, Morozko F, Salter PS, Moser S, Pong Z, Patel RB, Walmsley IA, Wang M, Hazan A, Barre N, Jesacher A, Fells J, He C, Katiyi A, Tian Z-N, Karabchevsky A, Booth MJet al., 2022,

    On-chip beam rotators, adiabatic mode converters, and waveplates through low-loss waveguides with variable cross-sections

    , LIGHT-SCIENCE & APPLICATIONS, Vol: 11, ISSN: 2047-7538
  • Journal article
    Danilov D, Tran T, Bearpark MJ, Marangos JP, Worth GA, Robb MAet al., 2022,

    How electronic superpositions drive nuclear motion following the creation of a localized hole in the glycine radical cation.

    , J Chem Phys, Vol: 156

    In this work, we have studied the nuclear and electron dynamics in the glycine cation starting from localized hole states using the quantum Ehrenfest method. The nuclear dynamics is controlled both by the initial gradient and by the instantaneous gradient that results from the oscillatory electron dynamics (charge migration). We have used the Fourier transform (FT) of the spin densities to identify the "normal modes" of the electron dynamics. We observe an isomorphic relationship between the electron dynamics normal modes and the nuclear dynamics, seen in the vibrational normal modes. The FT spectra obtained this way show bands that are characteristic of the energy differences between the adiabatic hole states. These bands contain individual peaks that are in one-to-one correspondence with atom pair (+·) ↔ (·+) resonances, which, in turn, stimulate nuclear motion involving the atom pair. With such understanding, we anticipate "designer" coherent superpositions that can drive nuclear motion in a particular direction.
  • Journal article
    Garratt D, Misiekis L, Wood D, Larsen EW, Matthews M, Alexander O, Ye P, Jarosch S, Ferchaud C, Strueber C, Johnson AS, Bakulin AA, Penfold TJ, Marangos JPet al., 2022,

    Direct observation of ultrafast exciton localization in an organic semiconductor with soft X-ray transient absorption spectroscopy

    , NATURE COMMUNICATIONS, Vol: 13
  • Journal article
    Schwickert D, Ruberti M, Kolorenc P, Usenko S, Przystawik A, Baev K, Baev I, Braune M, Bocklage L, Czwalinna MK, Deinert S, Duesterer S, Hans A, Hartmann G, Haunhorst C, Kuhlmann M, Palutke S, Roehlsberger R, Roensch-Schulenburg J, Schmidt P, Toleikis S, Viefhaus J, Martins M, Knie A, Kip D, Averbukh V, Marangos JP, Laarmann Tet al., 2022,

    Electronic quantum coherence in glycine molecules probed with ultrashort x-ray pulses in real time

    , SCIENCE ADVANCES, Vol: 8, ISSN: 2375-2548
  • Journal article
    Thekkadath G, Sempere-Llagostera S, Bell B, Patel R, Kim M, Walmsley Iet al., 2022,

    Experimental demonstration of Gaussian boson sampling with displacement

    , PRX Quantum, ISSN: 2691-3399
  • Journal article
    Song W, Lim Y, Jeong K, Ji Y-S, Lee J, Kim J, Kim MS, Bang Jet al., 2022,

    Quantum solvability of noisy linear problems by divide-and-conquer strategy

    , Quantum Science and Technology, Vol: 7, ISSN: 2058-9565

    Noisy linear problems have been studied in various science and engineering disciplines. A class of 'hard' noisy linear problems can be formulated as follows: Given a matrix $\hat{A}$ and a vector b constructed using a finite set of samples, a hidden vector or structure involved in b is obtained by solving a noise-corrupted linear equation $\hat{A}\mathbf{x}\approx \mathbf{b}+\boldsymbol{\eta }$, where η is a noise vector that cannot be identified. For solving such a noisy linear problem, we consider a quantum algorithm based on a divide-and-conquer strategy, wherein a large core process is divided into smaller subprocesses. The algorithm appropriately reduces both the computational complexities and size of a quantum sample. More specifically, if a quantum computer can access a particular reduced form of the quantum samples, polynomial quantum-sample and time complexities are achieved in the main computation. The size of a quantum sample and its executing system can be reduced, e.g., from exponential to sub-exponential with respect to the problem length, which is better than other results we are aware. We analyse the noise model conditions for such a quantum advantage, and show when the divide-and-conquer strategy can be beneficial for quantum noisy linear problems.
  • Journal article
    Zhang C, Zhang C, Cheng L, Steimle TC, Tarbutt MRet al., 2022,

    Inner-shell excitation in the YbF molecule and its impact on laser cooling

    , JOURNAL OF MOLECULAR SPECTROSCOPY, Vol: 386, ISSN: 0022-2852
  • Journal article
    Will C, Bohman M, Driscoll T, Wiesinger M, Abbass F, Borchert MJ, Devlin JA, Erlewein S, Fleck M, Latacz B, Moller R, Mooser A, Popper D, Wursten E, Blaum K, Matsuda Y, Ospelkaus C, Quint W, Walz J, Smorra C, Ulmer Set al., 2022,

    Sympathetic cooling schemes for separately trapped ions coupled via image currents

    , NEW JOURNAL OF PHYSICS, Vol: 24, ISSN: 1367-2630
  • Journal article
    Tang H, Banchi L, Wang T-Y, Shang X-W, Tan X, Zhou W-H, Feng Z, Pal A, Li H, Hu C-Q, Kim MS, Jin X-Met al., 2022,

    Generating Haar-uniform randomness using stochastic quantum walks on a photonic chip

    , Physical Review Letters, Vol: 128, ISSN: 0031-9007

    As random operations for quantum systems are intensively used in various quantum information tasks, a trustworthy measure of the randomness in quantum operations is highly demanded. The Haar measure of randomness is a useful tool with wide applications, such as boson sampling. Recently, a theoretical protocol was proposed to combine quantum control theory and driven stochastic quantum walks to generate Haar-uniform random operations. This opens up a promising route to converting classical randomness to quantum randomness. Here, we implement a two-dimensional stochastic quantum walk on the integrated photonic chip and demonstrate that the average of all distribution profiles converges to the even distribution when the evolution length increases, suggesting the 1-pad Haar-uniform randomness. We further show that our two-dimensional array outperforms the one-dimensional array of the same number of waveguide for the speed of convergence. Our Letter demonstrates a scalable and robust way to generate Haar-uniform randomness that can provide useful building blocks to boost future quantum information techniques.
  • Journal article
    Li S, Driver T, Rosenberger P, Champenois EG, Duris J, Al-Haddad A, Averbukh V, Barnard JCT, Berrah N, Bostedt C, Bucksbaum PH, Coffee RN, DiMauro LF, Fang L, Garratt D, Gatton A, Guo Z, Hartmann G, Haxton D, Helml W, Huang Z, LaForge AC, Kamalov A, Knurr J, Lin M-F, Lutman AA, MacArthur JP, Marangos JP, Nantel M, Natan A, Obaid R, O'Neal JT, Shivaram NH, Schori A, Walter P, Li Wang A, Wolf TJA, Zhang Z, Kling MF, Marinelli A, Cryan JPet al., 2022,

    Attosecond coherent electron motion in Auger-Meitner decay

    , SCIENCE, Vol: 375, Pages: 285-+, ISSN: 0036-8075
  • Journal article
    Moroney N, Del Bino L, Zhang S, Woodley MTM, Hill L, Wildi T, Wittwer VJ, Sudmeyer T, Oppo G-L, Vanner MR, Brasch V, Herr T, Del'Haye Pet al., 2022,

    A Kerr polarization controller

    , NATURE COMMUNICATIONS, Vol: 13
  • Journal article
    Sempere-Llagostera S, Thekkadath G, Patel R, Kolthammer WS, Walmsley Iet al., 2022,

    Reducing $g^{(2)}(0)$ of a parametric down-conversion source via photon-number resolution with superconducting nanowire detectors

    , Optics Express, Vol: 30, Pages: 3138-3147, ISSN: 1094-4087

    Multiphoton contributions pose a significant challenge for the realisation of heralded single-photon sources (HSPS) based on nonlinear processes. In this work, we improve the quality of single photons generated in this way by harnessing the photon-number resolving (PNR) capabilities of commercial superconducting nanowire single-photon detectors (SNSPDs). We report a 13 ± 0.4% reduction of g(2)(τ = 0), even with a collection efficiency in the photon source of only 29.6%. Our work demonstrates the first application of the PNR capabilities of SNSPDs and shows improvement in the quality of an HSPS with widely available technology.
  • Journal article
    Alsing PM, Birrittella RJ, Gerry CC, Mimih J, Knight PLet al., 2022,

    Extending the Hong-Ou-Mandel effect: the power of nonclassicality

    , Physical Review A: Atomic, Molecular and Optical Physics, Vol: 105, ISSN: 1050-2947

    We show that the parity (evenness or oddness) of a nonclassical state of light has a dominant influence on the interference effects at a balanced beam splitter, irrespective of the state initially occupying the other input mode. Specifically, the parity of the nonclassical state gives rise to destructive interference effects that result in deep valleys in the output joint number distribution of which the Hong-Ou-Mandel (HOM) effect is a limiting case. The counterintuitive influence of even a single photon to control the output of a beam splitter illuminated by any field, be it a coherent or even a noisy thermal field, demonstrates the extraordinary power of nonclassicality. The canonical example of total destructive interference of quantum amplitudes leading to the absence of coincidence counts from a 50:50 beam splitter (BS) is the celebrated HOM effect, characterized by the vanishing of the joint probability of detecting singe photons in each of the output beams. We show that this is a limiting case of more general input states upon which a 50:50 BS can create total, or near total, destructive interference of quantum amplitudes. For the case of an odd photon-number input Fock state of arbitrary value n>0 we show that the joint photon-number probabilities vanish when detecting identical photon numbers in each output beams. We specifically examine the mixing of photon-number states of n=1, 2, and 3 with a continuous-variable state, such as a coherent state of arbitrary amplitude, and a thermal state. These vanishing joint probabilities form what we call a central nodal line: A contiguous set of zeros representing complete destructive interference of quantum amplitudes. We further show that with odd or even photon-number Fock states n, with n>1, there will be additional off-diagonal curves along which the joint photon-number probabilities are either zero, or near zero, which we call pseudonodal curves, which constitute a near, but not complete, destructive inte
  • Journal article
    Kwon H, Mukherjee R, Kim MS, 2022,

    Reversing Lindblad dynamics via continuous Petz recovery map

    , Physical Review Letters, Vol: 128, Pages: 1-7, ISSN: 0031-9007

    An important issue in developing quantum technology is that quantum states are so sensitive to noise. We propose a protocol that introduces reverse dynamics, in order to precisely control quantum systems against noise described by the Lindblad master equation. The reverse dynamics can be obtained by constructing the Petz recovery map in continuous time. By providing the exact form of the Hamiltonian and jump operators for the reverse dynamics, we explore the potential of utilizing the near-optimal recovery of the Petz map in controlling noisy quantum dynamics. While time-dependent dissipation engineering enables us to fully recover a single quantum trajectory, we also design a time-independent recovery protocol to protect encoded quantum information against decoherence. Our protocol can efficiently suppress only the noise part of dynamics thereby providing an effective unitary evolution of the quantum system.
  • Journal article
    Ma Y, Guff T, Morley GW, Pikovski I, Kim MSet al., 2022,

    Limits on inference of gravitational entanglement

    , Physical Review Research, Vol: 4, Pages: 1-7, ISSN: 2643-1564

    Combining gravity with quantum mechanics remains one of the biggest challenges of physics. In the past years, experiments with opto-mechanical systems have been proposed that may give indirect clues about the quantum nature of gravity. In a recent variation of such tests [D. Carney et al., Phys.Rev.X Quantum 2, 030330 (2021)], the authors ropose to gravitationally entangle an atom interferometer with a mesoscopic oscillator. The interaction results in periodic drops and revivals of the interferometeric visibility, which under specific assumptions indicate the gravitational generation of entanglement. Here we study semi-classical models of the atom interferometer that can reproduce the same effect. We show that the core signature – periodic collapses and revivals of the visibility – can appear if the atom is subject to a random unitary channel, including the casewhere the oscillator is fully classical and situations even without explicit modelling of the oscillator. We also show that the non-classicality of the oscillator vanishes unless the system is very close to its ground state, and even when the system is in the ground state, the non-classicality is limitedby the coupling strength. Our results thus indicate that deducing ntanglement from the proposed experiment is very challenging, since fulfilling and verifying the non-classicality assumptions is a significant challenge on its own right.
  • Journal article
    Thekkadath GS, Bell BA, Patel RB, Kim MS, Walmsley IAet al., 2022,

    Measuring the joint spectral mode of photon pairs using intensity interferometry

    , Physical Review Letters, Vol: 128, Pages: 1-6, ISSN: 0031-9007

    The ability to manipulate and measure the time-frequency structure of quantum light is useful for information processing and metrology. Measuring this structure is also important when developing quantum light sources with high modal purity that can interfere with other independent sources. Here, we present and experimentally demonstrate a scheme based on intensity interferometry to measure the joint spectral mode of photon pairs produced by spontaneous parametric down-conversion. We observe correlations in the spectral phase of the photons due to chirp in the pump. We show that our scheme can be combined with stimulated emission tomography to quickly measure their mode using bright classical light. Our scheme does not require phase stability, nonlinearities, or spectral shaping and thus is an experimentally simple way of measuring the modal structure of quantum light.
  • Journal article
    Borchert MJ, Devlin JA, Erlewein SR, Fleck M, Harrington JA, Higuchi T, Latacz BM, Voelksen F, Wursten EJ, Abbass F, Bohman MA, Mooser AH, Popper D, Wiesinger M, Will C, Blaum K, Matsuda Y, Ospelkaus C, Quint W, Walz J, Yamazaki Y, Smorra C, Ulmer Set al., 2022,

    A 16-parts-per-trillion measurement of the antiproton-to-proton charge-mass ratio

    , NATURE, Vol: 601, Pages: 53-+, ISSN: 0028-0836
  • Conference paper
    Thekkadath GS, Sempere-Llagostera S, Bell BA, Patel RB, Kim MS, Walmsley IAet al., 2022,

    Experimental demonstration of Gaussian boson sampling with displacement

    We inject squeezed vacuum and weak coherent light into a multiport interferometer and measure the output photon statistics. Our work explores the capabilities of a displacement field in Gaussian boson sampling.
  • Journal article
    Bulmer JFF, Bell BA, Chadwick RS, Jones AE, Moise D, Rigazzi A, Thorbecke J, Haus U-U, Van Vaerenbergh T, Patel RB, Walmsley IA, Laing Aet al., 2022,

    The boundary for quantum advantage in Gaussian boson sampling

    , SCIENCE ADVANCES, Vol: 8, ISSN: 2375-2548
  • Conference paper
    Sempere-Llagostera S, Thekkadath GS, Patel RB, Kolthammer WS, Walmsley IAet al., 2022,

    Reducing g<sup>(2)</sup>(0) of a Parametric Down-Conversion Source via Photon-Number Resolution with Superconducting Nanowire Detectors

    We demonstrate a 13±0.4% reduction of the second-order correlation function g(2)(0) by harnessing the photon-number resolving capabilities of commercial superconducting nanowire single-photon detectors, improving the quality of a heralded single-photon source.
  • Journal article
    Corfield O, Lishman J, Lee C, Toba JM, Porter G, Heinrich JM, Webster SC, Mintert F, Thompson RCet al., 2021,

    Certifying Multilevel Coherence in the Motional State of a Trapped Ion

    , PRX QUANTUM, Vol: 2
  • Working paper
    Barontini G, Blackburn L, Boyer V, Butuc-Mayer F, Calmet X, Lopez-Urrutia JRC, Curtis EA, Darquie B, Dunningham J, Fitch NJ, Forgan EM, Georgiou K, Gill P, Godun RM, Goldwin J, Guarrera V, Harwood A, Hill IR, Hendricks RJ, Jeong M, Johnson MYH, Keller M, Sajith LPK, Kuipers F, Margolis HS, Mayo C, Newman P, Parsons AO, Prokhorov L, Robertson BI, Rodewald J, Safronova MS, Sauer BE, Schioppo M, Sherrill N, Stadnik YV, Szymaniec K, Tarbutt MR, Thompson RC, Tofful A, Tunesi J, Vecchio A, Wang Y, Worm Set al., 2021,

    Measuring the stability of fundamental constants with a network of clocks

    , Publisher: arXiv

    The detection of variations of fundamental constants of the Standard Modelwould provide us with compelling evidence of new physics, and could lift theveil on the nature of dark matter and dark energy. In this work, we discuss howa network of atomic and molecular clocks can be used to look for suchvariations with unprecedented sensitivity over a wide range of time scales.This is precisely the goal of the recently launched QSNET project: A network ofclocks for measuring the stability of fundamental constants. QSNET will includestate-of-the-art atomic clocks, but will also develop next-generation molecularand highly charged ion clocks with enhanced sensitivity to variations offundamental constants. We describe the technological and scientific aims ofQSNET and evaluate its expected performance. We show that in the range ofparameters probed by QSNET, either we will discover new physics, or we willimpose new constraints on violations of fundamental symmetries and a range oftheories beyond the Standard Model, including dark matter and dark energymodels.
  • Journal article
    Enzian G, Freisem L, Price JJ, Svela AO, Clarke J, Shajilal B, Janousek J, Buchler BC, Lam PK, Vanner MRet al., 2021,

    Non-Gaussian Mechanical Motion via Single and Multiphonon Subtraction from a Thermal State

    , PHYSICAL REVIEW LETTERS, Vol: 127, ISSN: 0031-9007

This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.

Request URL: http://wwwtest.imperial.ac.uk:80/respub/WEB-INF/jsp/search-t4-html.jsp Request URI: /respub/WEB-INF/jsp/search-t4-html.jsp Query String: id=213&limit=30&resgrpMemberPubs=true&respub-action=search.html Current Millis: 1765814214818 Current Time: Mon Dec 15 15:56:54 GMT 2025