Emblem of the collaboration

Overview

The Standard Model has been extremely successful in making experimental predictions in the past decades, yet leaves some key phenomena unexplained. In particular, it does not include gravity and does not explain dark matter. We are a consortium of UK universities creating a world-leading multidisciplinary programme to search for dark matter and for quantum aspects of space-time. Both of these research directions use the common technological platform of quantum-enhanced interferometry. We leverage expertise developed within the National Quantum Technology Programme in optical resonators, quantum sources of light, and single photon detectors to address the fundamental physics problems.

Our first research direction is devoted to searches for dark matter and other particles beyond the Standard Model. There are many theories that try to explain the nature of dark matter. Analyses of a range of observations, including the rotation velocities of galaxies, the dynamics of galaxy clusters, microlensing, and the large-scale structure of the universe led most of the scientific community to accept non-baryonic particles as the primary dark matter candidates. Weakly interacting massive particles (WIMPs) were the most promising candidate over the last few decades. However, a set of ultra-sensitive WIMP detectors, such as XENON, LUX, and PandaX, have not observed dark matter to date and will reach the neutrino background in the near future. Therefore, we search for the other very promising non-baryonic dark matter candidates: axions and axion-like-particles.

Our second research direction searches for quantum aspects of space-time. Quantum mechanics and the general theory of relativity have successfully passed all experimental tests to date. For example, quantisation of the motion of a macroscopic object has recently been demonstrated. And propagation of errors in modern quantum computers, such as Google’s Sycamore does not show any signs of unexpected decoherence in a highly entangled state. At the same time, recent observation of gravitational waves from binary black holes and binary neutron star mergers proved that the general theory of relativity also holds in a very strong gravitational field. The main related and long-standing research question is: How can gravity be united with the other fundamental forces? To seek answers that inform this question, we propose to study two quantum aspects of space-time.

Projects

Our research programme Quantum-enhanced Interferometry for New Physics is funded by the UKRI Science and Technology Facilities Council and Engineering and Physical Sciences Research Council under the Quantum Technologies for Fundamental Physics initiative.

Axion layout
Axion lab
Axion sensitivity

Axion interferometer

There are many theories that try to explain the nature of dark matter. Analyses of a range of observations, including the rotation velocities of galaxies, the dynamics of galaxy clusters, microlensing, and the large-scale structure of the universe led most of the scientific community to accept non-baryonic particles as the primary dark matter candidates.

The physical principle of axion-like-particle searches pursuits by our group is to explore a phase velocity difference between left- and right-handed circularly polarized light which propagates in the presence of axion-like-particle fields. We build a quantum-enhanced interferometer to measure the phase difference induced by axions with masses from 10-16 eV up to 10-8 eV.

Figures:

Figure 1: Layout of the experiment

Figure 2: Plan of the laboratory (currently under construction)

Figure 3: Expected sensitivity

Selected publications:

Quantum-enhanced interferometry for axion searches

Searching for axion dark matter with birefringent cavities

For more information contact: Haixing Miao, Vincent Boyer, Denis Martynov

ALPS scheme
ALPS vacuum
TES

Any light particle search

We are building an advanced superconducting transition-edge-sensor (TES) platform to enhance the ALPS sensitivity. This quantum detector will be built in collaboration with DESY and NIST. The project will position the UK as a key partner in the ALPS collaboration, which has ambitious goals to build the next generation of detectors in a km-scale facility.

The ALPS experiment is currently in its second generation under a collaboration of DESY, University of Florida, the Max-Planck-Institute (AEI) in Hannover, Mainz University, and Cardiff University. The ALPS setup does not rely on the assumption that axions, axion-like-particles, and other weakly interacting slim particles (WISPs) account for dark matter in the galactic halo. Instead, the instrument creates and detects its own axions via a large-scale "light-shining-through-a-wall" experiment. WISPs are produced in a 5.3 T magnetic field inside a 120-m long optical resonator, travel through a dark screen, convert back to photons in an identical resonator, and are detected on a single photon detector.

Figures:

Figure 1: Layout of the experiment

Figure 2: Picture of the ALPS vacuum tubes. Image credit: DESY/Marta Mayer

Figure 3: transition edge sensor

Selected publications:

Design of the ALPS II Optical System

Superfast photon counting

For more information contact: Robert Hadfield, Dmitry Morozov, Hartmut Grote

Holometer Scheme
Holometer lab
Holometer noise

Quantisation of space-time

This project is related to the holographic principle, which states that the information content of a volume of space can be encoded on a lower-dimensional boundary of that volume. Certain theoretical models of the holographic principle suggest space-time correlations that can be measured by a pair of co-located optical interferometers.

Some models were tested by the Fermilab Holometer experiment and null results obtained. We propose to build a more sensitive and flexible table-top setup which can be adjusted to study a wider range of models of holographic correlations, including implications from an exciting development arising from new observations of angular correlations in the CMB background.

Figures:

Figure 1: Layout of the experiment

Figure 2: Picture of the laboratory

Figure 3: Expected sensitivity of the experiment

Selected publications:

An Experiment for Observing Quantum Gravity Phenomena using Twin Table-Top 3D Interferometers.

For more information contact: Kate Dooley, Hartmut Grote, Animesh Datta

SQL layout
SQL cryostat
SQL sus model

Cryogenic silicon optomechanics

Cryogenic silicon technology promises significant reduction of thermal noises and is considered by the GW community as the key element of the future GW antennas, such as Cosmic Explorer and Einstein Telescope. In this experiment, we explore macroscopic quantum mechanics phenomena, such as quantum back-action noise, with silicon mirrors.

In our group, we are building an experiment that will show the feasibility of preparing a macroscopic quantum-limited system within a regular laboratory environment. This will be achieved by suspending a cryogenically cooled, high-finesse optical cavity via a multi-stage suspension. We motivate the utility of our experiment in providing an increased understanding of the nature of quantum fluctuations in current and future gravitational wave detectors, as well as opening an avenue for research into aspects of macroscopic quantum mechanics and quantum gravity.

Figures:

Figure 1: Layout of the experiment

Figure 2: Manufactured parts of the suspension system

Figure 3: CAD model of the suspension system

Selected publications:

Towards the Standard Quantum Limit in a Table-Top Interferometer

Quantum correlations of light mediated by gravity

For more information contact: Jiri (George) Smetana, Stuart Reid, Denis Martynov

Technology

Optical cavities

Optical cavities

Optical cavities are at the core of many modern experiments, including gravitational-wave detectors, optical atomic clocks, and quantum optomechanical experiments. Laser light bouncing thousands of times between the cavity mirrors provides the world-best readout technique of the mirror position within the cavity.

In our group, we develop new optical interferometers to search for dark matter, quantisation of space-time, and semiclassical gravity.

Figure: LIGO vacuum equipment. Credit: LIGO MIT.

Selected publications:

Sensitivity of the Advanced LIGO detectors at the beginning of gravitational wave astronomy

For more information contact: Hartmut Grote, Denis Martynov

Squeezed Light

Squeezed light

Precision measurement has been a primary driving force for advancing modern science. But how can we further improve optical measurements? The fundamental limit to their precision comes from the quantum nature of light. Poissonian distribution of the photon number in the laser beam cases quantum shot and back-action noises on photodiodes and suspended mirrors.

In our group, we study two approaches towards the suppression of quantum noises. First, we optimise the response of gravitational-wave antennas to signals in a particular frequency band. Second, we explore a new paradigm using quantum amplification that complements the squeezing technique and is robust against optical losses..

Figure: Squeezed light. Credit: A. Franzen and T. Steinhaus.

Selected publications:

First demonstration of 6 dB quantum noise reduction in a kilometer scale gravitational wave observatory

Proposal for Gravitational-Wave Detection Beyond the Standard Quantum Limit via EPR Entanglement

For more information contact: Kate Dooley, Hartmut Grote, Vincent Boyer.

TES

Transition edge sensors

The past decade has seen a dramatic increase in interest in new single-photon detector technologies. A major cause of this trend has undoubtedly been the push towards optical quantum information applications. These new applications place extreme demands on detector performance that go beyond the capabilities of established single-photon detectors.

The ALPS II photosensor is a tungsten transition-edge sensor (W-TES) optimized for 1064 nm photons. This TES, operated at 80 mK, has already allowed single infrared photon detections as well as non-dispersive spectroscopy with very low background rates. In our group, we develop a new TES to further reduce number of dark counts in the detectors.

Figure: Transition edge sensors. Credit: NIST.

Selected publications:

Single-photon detectors for optical quantum information applications

Quantum Efficiency Characterization and Optimization of a Tungsten Transition-Edge Sensor for ALPS II

For more information contact: Robert Hadfield, Dmitry Morozov

Optical coatings

Optical coatings

Extreme-performance optical coatings are essential for both scientific and industrial applications. In particular, gravitational-wave detectors are limited by coating thermal noise in their most sensitive frequency band. We also need better coatings for photonics and laser applications, particularly for increasing the laser damage threshold, and for optical atomic clocks.

Amorphous silicon has ideal properties for many applications in fundamental research and industry. However, the optical absorption is often unacceptably high, particularly for gravitational-wave detection. In our group, we develop a novel ion-beam deposition method for fabricating amorphous silicon with unprecedentedly low unpaired electron-spin density and optical absorption.

Figure: Optical coatings. Credit: EGO/Virgo Collaboration/Perciballi.

Selected publications:

Amorphous Silicon with Extremely Low Absorption: Beating Thermal Noise in Gravitational Astronomy

For more information contact: Stuart Reid, Denis Martynov

Collaboration

Vincent Vincent Boyer
University of Birmingham
Experimental quantum optics
Equality, diversity and inclusion officer
Animesh Animesh Datta
University of Warwick
Theoretical quantum optics
Kate Kate Dooley
Cardiff University
Experimental quantum optics
Hartmut Hartmut Grote
Principal Investigator
Cardiff University
Holographic noise
Robert Robert Hadfield
University of Glasgow
Single photon detectors
Denis Denis Martynov
University of Birmingham
Dark matter
Semiclassical gravity
Haixing Haixing Miao
University of Birmingham
Dark matter
Semiclassical gravity
Stuart Stuart Reid
University of Strathclyde
Optical coatings
Dmitry Dmitry Morozov
University of Glasgow
Research Fellow
Single photon detectors
George Jiri (George) Smetana
University of Birmingham
PhD student
Cryogenic silicon
SteveBeaumont Steve Beaumont
Project Partner
QUANTIC
Single photon detectors
KaiBongs Kai Bongs
Project Partner
QH in Sensors and Timing
Optical cavities
YanbeiChen Yanbei Chen
Project Partner
Caltech
Semiclassical gravity
MatthewEvans Matthew Evans
Project Partner
MIT
Dark matter
CraigHogan Craig Hogan
Project Partner
Fermilab
Holographic noise
AxelLindner Axel Lindner
Project Partner
DESY
ALPS II experiment
MoritzMehmet Moritz Mehmet
Project Partner
AEI Hannover
Quantum optics
SaeWooNam Sae Woo Nam
Project Partner
NIST
Single photon detectors
HenningVahlbruch Henning Vahlbruch
Project Partner
AEI Hannover
Quantum optics

Join Us

PhD positions:

Every year our groups offer new PhD positions to drive our experimental effort forward. The list of available 2021 PhD projects is listed below:

University of Glasgow: Detecting Dark Matter

Quantum technologies such as superconducting single-photon detectors offer a new route to detecting dark matter through the axion-photon interaction. The Quantum Sensors group led by Professor Robert Hadfield at the University of Glasgow is answering this challenge. Working with our international partners we will provide advanced superconducting single-photon detectors for the ALPS experiment at DESY, Hamburg, Germany. This will boost the sensitivity of this important search experiment and may even succeed in capturing the first signature of Dark Matter. Your PhD research will be aligned with this exciting international effort. You will fabricate advanced superconducting photon counting detectors in the James Watt Nanofabrication Centre at the University of Glasgow, gain expertise in precision cryogenic single-photon detection measurements in the Quantum Sensors group, and participate in the upgrade of the ALPS detectors. This is an exciting opportunity for a physics graduate with an appetite for hands on experimental research, or an engineering graduate who is motivated by the mysteries of the universe. Closing date for scholarship applications 31st January 2021. Interested candidates should contact Professor Robert Hadfield in advance of submitting an application.

University of Birmingham: Cryogenic Silicon Optomechanics

Quantum mechanics has triggered the development of the crucial technology for modern optical precision measurements: lasers. However, the Heisenberg uncertainty principle for the amplitude and phase quadrature of the laser field sets fundamental limits on the precision of the interferometric measurements. Quantum back-action noise on the LIGO mirrors from the laser field degrades the detector sensitivity below 30 Hz. Quantum shot noise in the LIGO photodetectors limits its sensitivity above 100 Hz. The aim of this project is to experimentally observe quantum noises and investigate its properties, such as quantum correlations. The quantum noise arises due to the interference of vacuum fields and static laser fields inside optical cavities and drives suspended mirrors with a random force. Members of our group currently set up an experiment with high-finesse suspended optical cavities which are compact prototypes of the km-scale LIGO detectors. PhD student will acquire skills in quantum optics, electronics, laser physics, feedback control, vibration isolation systems, data analysis. The project will include both experimental and theoretical work as well as simulations of quantum interactions.

University of Birmingham: Optical Coatings

Optical cavities are in the core of many precision instruments, such as optical atomic clocks, gravitational-wave detectors, optical rotation sensors, and quantum opto-mechanical setups. In this project, PhD student will investigate the properties of the key components of optical resonators: optical coatings. These thin films reflect light from the mirror surfaces and are formed by alternating layers of materials with different refractive indices. Optical coatings can be manufactured in a variety of configurations. In particular, number, thickness, and even material of alternative layers can be varied to minimise optical losses and coating noises. PhD student will experimentally investigate properties of the state-of-the-art coatings in a multi-mode optical resonator in collaboration with the members of UK National Quantum Hub in Sensors and Timing.

University of Birmingham: Axion Interferometer

The Standard Model has been extremely successful in making experimental predictions in the past decades, yet leaves some key phenomena unexplained. In particular, it does not include gravity and does not explain dark matter. There are many theories that try to explain the nature of dark matter. Analyses of a range of observations, including the rotation velocities of galaxies, the dynamics of galaxy clusters, microlensing, and the large-scale structure of the universe led most of the scientific community to accept non-baryonic particles as the primary dark matter candidates. Axions and axion-like-particles are promising dark matter candidates. PhD student will help build a tabletop optical interferometer to hunt for axion-like-particles and acquire skills in precision measurements, quantum optics, data analysis, control theory, and laser physics.

Postdoc positions:

Cardiff University: experimental search for particles beyond the standard model

Applications are invited for a postdoctoral position in experimental search for particles beyond the standard model, in particular for work at the “Any Light Particle Search” (ALPS) II experiment at DESY in Hamburg, Germany. This experiment searches for Axion-like particles, that may also be a part of the mysterious dark matter. You will participate in the commissioning of the ALPS II experiment, in conducting measurement campaigns, analysing and interpreting data, and planning for possible future upgrades of the ALPS II facility and possibly related experiments. This post is part of a consortium involving experimental and theoretical groups at Birmingham (Boyer, Martynov, Miao), Glasgow (Hadfield), and Strathclyde (Reid). Employment is by Cardiff University, but the post holder is expected to spend a majority of the time at DESY in Hamburg.

Send your questions about jobs to

Warwick: Animesh Datta

Cardiff: Hartmut Grote

Glasgow: Robert Hadfield

Birmingham: Denis Martynov

Strathclyde: Stuart Reid

News