Emblem of the collaboration

Quantum-enhanced Interferometry for New Physics

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

Lorenzo Lorenzo Aiello
Cardiff University
Research Associate
Experimental quantum optics
Vincent Vincent Boyer
University of Birmingham
Experimental quantum optics
Equality, diversity and inclusion officer
Animesh Animesh Datta
University of Warwick
Theoretical quantum optics
Artemiy Artemiy Dmitriev
University of Birmingham
Research Fellow
Dark matter
Kate Kate Dooley
Cardiff University
Experimental quantum optics
Lorenzo Aldo Ejlli
Cardiff University
Research Associate
Experimental quantum optics
Hartmut Hartmut Grote
Principal Investigator
Cardiff University
Holographic noise
Robert Robert Hadfield
University of Glasgow
Single photon detectors
Joscha Joscha Heinze
Research Fellow
Dark matter
Quantum optics
Kanioar Kanioar Karan
University of Cardiff
Research Fellow
Experimental quantum optics
Denis Denis Martynov
Deputy PI
University of Birmingham
Dark matter
Semiclassical gravity
Haixing Haixing Miao
University of Birmingham
Dark matter
Semiclassical gravity
Devendra Devendra Kumar Namburi
University of Glasgow
Research Fellow
Single photon detectors
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
Research Fellow
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
Tianliang Yan Tianliang Yan
University of Birmingham
Research fellow
Cryogenic silicon

Our oversight committee and advisory board

Clare Clare Burrage
University of Nottingham
James Hough James Hough
University of Glasgow
Alex Lvovsky Alexander Lvovsky
University of Oxford
Paola Arias Reyes Paola Arias Reyes
Universidad de Santiago de Chile
Kamalam Vanninathan Kamalam Vanninathan
STFC
Stafford Withington Stafford Withington
University of Cambridge

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:

Cardiff University: Searching for Quantization of Space-time with quantum-enhanced interferometers.

Laser interferometers have long been used to probe fundamental physics phenomena, from disproving the existence of the theorized ether well over a hundred years ago to making the first direct detections of gravitational waves in recent years. Given the extraordinary measurement precision that can be achieved with the latest technological advances in laser interferometer design, they can now also be used for challenging questions in fundamental physics, such as searching for the potential quantization of spacetime, dark matter, and ultra-high frequency gravitational waves. In our labs in Cardiff we are in the process of building the most sensitive table-top interferometer to date, including non-classical states of light such as squeezed light to improve sensitivity. Should you join our team, a potential project could be the development of our high-frequency data-acquisition system (which samples 8 channels with 500 Million samples per second each) and its data-analysis pipelines. These pipelines search for signs of quantization of spacetime, dark matter, and high-frequency gravitational waves. This unique precision experiment also provides exciting opportunities for working on other systems, such as adaptive optics that can be controlled with machine learning techniques, and adaptive interferometer feedback control and noise analysis techniques.

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.

Postdoc positions:

University of Birmingham: research fellow in precision measurements. Apply now!

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 order to advance precision measurements, we are building a facility to measure properties of the key components of optical resonators: optical coatings. Our measurement procedure is a crucial step in manufacturing high-quality coatings because we need to experimentally explore the whole parameter space of coating production, such as deposition rate, doping materials, and annealing.

Faculty positions:

University of Birmingham: Assistant/assosiate professor in experimental physics. Apply now!

The School of Physics and Astronomy and Institute for Gravitational Wave Astronomy invite applications for three faculty positions in areas relevant to gravitational-wave and multi-messenger astronomy, including experimental physics, gravitational-wave instrumentation, observational astronomy, theoretical astrophysics and general relativity. The Institute for Gravitational Wave Astronomy has a rich portfolio of research activities in experimental physics, instrumentation, data analysis and observations, theoretical astrophysics and general relativity, and transients and multi-messenger astronomy. Institute members play active roles in the GEO Collaboration and the LIGO Scientific Collaboration – including the development of next generation ground-based gravitational-wave observatories – the LISA Consortium, the European and International Pulsar Timing Array Collaboration, and surveys such as ENGRAVE, ePESSTO+ and LSST. The Institute has excellent laboratory and computer facilities. The Institute is affiliated with the Astrophysics and Space Research group, one of the eight research groups in the School of Physics and Astronomy.

Send your questions about jobs to

Warwick: Animesh Datta

Cardiff: Hartmut Grote

Glasgow: Robert Hadfield

Birmingham: Denis Martynov

Strathclyde: Stuart Reid

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