A5062134456- Quantum Information and Cryptography
- Quantum Mechanics and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Subatomic Physics Research
- Quantum Computing Algorithms and Architecture
- Advanced Frequency and Time Standards
- Mechanical and Optical Resonators
- Quantum, superfluid, helium dynamics
- Quantum optics and atomic interactions
- Advanced Thermodynamics and Statistical Mechanics
- Photonic and Optical Devices
- Statistical Mechanics and Entropy
- Dark Matter and Cosmic Phenomena
- Orbital Angular Momentum in Optics
- Neural Networks and Reservoir Computing
- Noncommutative and Quantum Gravity Theories
- Strong Light-Matter Interactions
- Quantum many-body systems
- Reproductive tract infections research
- Advanced Fiber Laser Technologies
- Electrostatics and Colloid Interactions
- Human Resource and Talent Management
- Geophysics and Sensor Technology
- Diffusion and Search Dynamics
- Sparse and Compressive Sensing Techniques
University of Sussex
2016-2025
Sussex County Community College
2024
University of Leeds
2006-2013
Google (United States)
2007
University of Oxford
1999-2005
University of Auckland
1997-1998
Abstract We propose in this White Paper a concept for space experiment using cold atoms to search ultra-light dark matter, and detect gravitational waves the frequency range between most sensitive ranges of LISA terrestrial LIGO/Virgo/KAGRA/INDIGO experiments. This interdisciplinary experiment, called Atomic Experiment Dark Matter Gravity Exploration (AEDGE), will also complement other planned searches exploit synergies with wave detectors. give examples extended sensitivity matter offered...
We introduce a general model for network of quantum sensors, and we use this to consider the following question: When can entanglement between and/or global measurements, enhance precision with which measure set unknown parameters? rigorously answer question by presenting precise theorems proving that broad class problems there is, at most, very limited intrinsic advantage using entangled states or measurements. Moreover, many estimation separable local measurements are optimal, achieve...
This document presents a summary of the 2023 Terrestrial Very-Long-Baseline Atom Interferometry Workshop hosted by CERN. The workshop brought together experts from around world to discuss exciting developments in large-scale atom interferometer (AI) prototypes and their potential for detecting ultralight dark matter gravitational waves. primary objective was lay groundwork an international TVLBAI proto-collaboration. collaboration aims unite researchers different institutions strategize...
A longstanding problem in quantum metrology is how to extract as much information possible realistic scenarios with not only multiple unknown parameters, but also limited measurement data and some degree of prior information. Here we present a practical solution this: We derive Bayesian multi-parameter bound, construct the optimal when our bound can be saturated for single shot, consider experiments involving repeated sequence these measurements. Our method properly accounts number...
Abstract We summarise the discussions at a virtual Community Workshop on Cold Atoms in Space concerning status of cold atom technologies, prospective scientific and societal opportunities offered by their deployment space, developments needed before atoms could be operated space. The technologies discussed include atomic clocks, quantum gravimeters accelerometers, interferometers. Prospective applications metrology, geodesy measurement terrestrial mass change due to, e.g., climate change,...
We discuss a scheme for using entangled Bose-Einstein condensates to detect phase differences with resolution better than the standard quantum limit. To date, schemes have shown that enhancement in gained by entangling is lost when dissipation present. Here we show how this can be overcome number correlated condensates, as been produced recently laboratory. also outline measuring not destroyed effects of finite detector efficiency are considered.
Quantum metrology protocols are typically designed around the assumption that we have an abundance of measurement data, but recent practical applications increasingly driving interest in cases with very limited data. In this regime best approach involves interesting interplay between amount data and prior information. Here propose a new way optimising these schemes based on practically-motivated sequence identical independent measurements. For given probe state take our to be one for single...
Abstract The detection of variations fundamental constants the Standard Model would provide us with compelling evidence new physics, and could lift veil on nature dark matter energy. In this work, we discuss how a network atomic molecular clocks can be used to look for such unprecedented sensitivity over wide range time scales. This is precisely goal recently launched QSNET project: A measuring stability constants. will include state-of-the-art clocks, but also develop next-generation highly...
There has been a great deal of debate surrounding the issue whether it is possible for single photon to exhibit nonlocality. A number schemes have proposed that claim demonstrate this effect, but each met with significant opposition. The objections hinge largely on fact these use unobservable initial states and so, claimed, they do not represent experiments could actually be performed. Here we show how overcome by presenting an experimentally feasible scheme uses realistic states....
The theoretical framework for networked quantum sensing has been developed to a great extent in the past few years, but there are still number of open questions. Among these, problem significance, both fundamentally and constructing efficient networks, is that role inter-sensor correlations simultaneous estimation multiple linear functions, where latter taken over collection local parameters can thus be seen as global properties. In this work we provide solution when each node qubit state...
Two-party secure quantum remote sensing protocols enable quantum-enhanced measurements at locations with guaranteed security against eavesdroppers. This idea can be scaled up to networks of nodes where one party directly measure functions parameters the different using entangled states. However, on such decreases exponentially number nodes. Here we show how this problem overcome in a hybrid protocol that utilizes both and separable states achieve measurement precision any size. Published by...
Abstract We show how robust magnon-magnon (or photon-magnon) entanglement and asymmetric quantum steering can be achieved in a nonlinear cavity-magnon system composed of microwave cavity two yttrium-iron-garnet (YIG) spheres, which are each driven by external driving fields. The self-Kerr nonlinearity (SKN) magnons drives this behaviour we study two-fold periodically-modulated fields influence the dynamics. find that beating occurs both classical average mode between modes. Moreover, use...
Quantum metrology exploits quantum correlations to make precise measurements with limited particle numbers. By utilizing inter- and intramode in an optical interferometer, we find a state that combines entanglement squeezing give sevenfold enhancement the Fisher information (QFI)---a metric related precision---over shot-noise limit, for low photon Motivated by practicality then look at squeezed cat state, which has recently been made experimentally, shows further precision gains over limit...
Many results in the quantum metrology literature use Cramér-Rao bound and Fisher information to compare different estimation strategies. However, there are several assumptions that go into construction of these tools, limitations sometimes not taken account. While a strategy utilises this method can considerably simplify problem is valid asymptotically, have rigorous fair comparison we need adopt more general approach. In work methodology based on Bayesian inference understand what happens...
We discuss practical schemes for using entangled Bose-Einstein condensates to detect phase shifts with a resolution better than the shot-noise limit. begin by outlining procedure demonstrating how squeezed matter waves can be used make measurements simply lowering and raising potential barrier between two condensates. The shift is read out scheme which involves releasing studying collapses revivals of visibility observed interference fringes. Finally we show this could extended other...
We address some of the most commonly raised questions about entanglement, especially with regard to so-called occupation number entanglement. To answer unambiguously whether entanglement can exist in a one-atom delocalized state, we propose an experiment capable showing violations Bell's inequality using only this state and local operations. review previous discussions for one-photon non-locality specific creating entangled states, that superselection rule atom be overcome. As by-product,...
The advent of increasingly precise gyroscopes has played a key role in the technological development navigation systems. Ring-laser and fiber-optic gyroscopes, for example, are widely used modern inertial guidance systems rely on interference unentangled photons to measure mechanical rotation. sensitivity these devices scales with number particles as $1/\sqrt{N}$. Here we demonstrate how, by using sources entangled particles, it is possible do better even achieve ultimate limit allowed...
We consider the calibration of an optical quantum gyroscope by modeling two Sagnac interferometers, mounted approximately at right angles to each other. Reliable operation requires that we know angle between interferometers with high precision, and show a procedure akin multiposition testing in inertial navigation systems can be generalized case interferometry. find while entanglement is key resource within individual interferometer, its presence far more complicated story. The optimum level...
We present a scheme for creating macroscopic superpositions of the direction superfluid flow around loop. Using Bose–Hubbard model, we study an array Bose–Einstein condensates (BECs) trapped in optical potentials and coupled to one another form ring. By rotating ring so that each particle acquires on average half quantum flow, it is possible create multiparticle superposition all particles stationary. Under certain conditions scale up number superposition. The simplicity model has allowed us...
Recent work has argued that the concepts of entanglement and nonlocality must be taken seriously even in systems consisting only a single particle. These treatments, however, are nonrelativistic and, if particle is fundamental, it should also persist relativistic description. Here we consider spin-1/2 superposition two different velocities as viewed by an observer relativistically-boosted inertial frame. We show survives right up to speed light boosted would see single-particle violations...
In optical interferometry multi-mode entanglement is often assumed to be the driving force behind quantum enhanced measurements. Recent work has shown this assumption false: single mode states perform just as well their entangled counterparts. We go beyond show that when photon losses occur - an inevitability in any realistic system actually detrimental obtaining specifically apply idea a superposition of coherent states, demonstrating these robustness loss allows them significantly...
By exploiting the correlation properties of ultracold atoms in a multimode interferometer, we show how quantum enhanced measurement precision can be achieved with strong robustness to particle loss. While potential for is limited even moderate loss two-mode schemes, schemes more robust. A ring interferometer sensing rotational motion noninteracting fermionic realize an uncertainty scaling $1/(N\sqrt{\ensuremath{\eta}})$ $N$ particles fraction $\ensuremath{\eta}$ remaining after loss, which...