Emblem of the Birmingham GW Institute

Overview

The LIGO and Virgo gravitational-wave (GW) detectors are the most sensitive distance meters ever buit. During the latest science run, they achieved a precision of 1 part in 1023 for the distance fluctuations between the two mirrors separated by 4 km. This precision has allowed the astrophysics community to observe GW from black holes and neutron stars, test the general theory of relativity in the strongest gravitational regime, estimate population of compact objects in the universe, and even measure the Hubble constant.

The LIGO detectors became successful due the state-of-the-arm technologies developed by the collaborators world-wide. Birmingham has been a part of the Advanced LIGO UK Project from the outset. We developed and built sensors, actuators and control electronics for the instrument’s suspensions, a decisive sub-system that enabled the detections. The next generation of these devices for the A+ upgrade are under development in our group now. In parallel, we have carried out a much broader range of commissioning activities throughout LIGO O1-O3 observing runs.

Our experimental group is a part of the Birmingham Institute for Gravitational Wave Astronomy and Astrophysics and Space Research Group, where we apply our expertise in instrumentation and LIGO commissioning to the wide-ranging experimental R&D programme. Join our group to develop new technologies for future GW detectors, study quantum optomechanics, and search for axion dark matter. We are members of the Quantum Interferometry (QI) collaboration where apply precision measurement techniques to fundamental physics problems.

Research

LIGO chambers

Future detectors

The discoveries made by the LIGO and Virgo gravitational-wave detectors have had a transformative impact and triggered a new era in astronomy. Taking full advantage of the GW window requires a new network of observatories that can survey the Universe on its largest scales and provide information of broad interest in astrophysics, cosmology, and nuclear physics.

In our group, we work on the design of the future gravitational-wave detectors which can be hosted in the current or future facilities. In particular, we proposed an optical layout for observing signals from neutron star oscillations above 1 kHz. We also studied the low-frequency performance of the LIGO detectors and proposed a strategy to observe signals from intermediate-mass black holes below 30 Hz.

Figure: LIGO vacuum equipment. Credit: LIGO MIT.

Selected publications:

Exploring the sensitivity of gravitational wave detectors to neutron star physics

Prospects for Detecting Gravitational Waves at 5 Hz with Ground-Based Detectors

Towards the design of gravitational-wave detectors for probing neutron-star physics

Related experimental projects: Cryogenic silicon, 6D Seismometer

For more information contact: Haixing Miao, Denis Martynov

LIGO optics

Quantum optics

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: LIGO vacuum equipment. Credit: EGO/Virgo Collaboration/Perciballi.

Selected publications:

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

Quantum correlation measurements in interferometric gravitational-wave detectors

Related experimental projects: Cryogenic silicon, Quantum amplifiers

For more information contact: Haixing Miao, Denis Martynov, Teng Zhang.

L4C with optical readout

Seismic isolation

Sensors and actuators are the key pieces of hardware responsible for keeping the LIGO detectors in the linear regime. State-of-the-art seismic isolation system in the LIGO detectors is particularly important for studying intermediate-mass black holes, for localisation, and for accumulating signal-to- noise ratio from lighter sources.

In our group, we pursuits three research directions to improve seismic isolation of the future LIGO detectors: (i) a 6D seismometer for isolating the LIGO optical tables from the environment, (ii) cryogenic position sensors for future gravitational-wave detectors, (iii) interferometric position sensors to improve the sensitivity of the LIGO detectors at low frequencies.

Figure: L4C geophones with optical readout. Credit: Sam Cooper.

Selected publications:

A 6D interferometric inertial isolation system

A compact, large-range interferometer for precision measurement and inertial sensing

Sensors and actuators for the Advanced LIGO mirror suspensions

Related experimental projects: Position sensors, 6D Seismometer

For more information contact: Haixing Miao, Denis Martynov

Axion field

Dark matter

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. It is essential to increase the number of searches for the other very promising non-baryonic dark matter candidates: axions and axion-like-particles.

In our group, we build a novel quantum-enhanced interferometer to measure this axion-like-particle-induced phase difference between the two polarisation eigen modes of the optical cavity. If successful, our layout can be utilised in the LIGO facilities for the axion searches when new longer gravitational-wave facilities become available in the 2030s.

Figure: Artist's representation of axions. Credit: Quanta magazine.

Selected publications:

Quantum-enhanced interferometry for axion searches

Related experimental projects: Axion interferometer

For more information contact: Haixing Miao, Denis Martynov

Projects

SQL cryostat
SQL sus model
SQL layout

QTFP 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.

The research project is a part of the Quantum-enhanced Interferometry for New Physics programme that 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.

Figures:

Figure 1: Manufactured parts of the suspension system

Figure 2: CAD model of the suspension system

Figure 3: Layout of the experiment

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, Denis Martynov

6D design
6D Fused Silica Mass
6D ISI motion

STFC 6D seismometer

Pushing this seismic wall in GW detectors to lower frequencies will have two critical effects: expansion of the astrophysical reach and reduction of the impact of environmental disturbances on the observatories. We propose to solve the problem of ground vibrations with a 6D seismometer which measures the bench motion in all 6 degrees of freedom with optical sensors.

In our group, we perform the full set of tasks related to the development of the 6D seismometer: simulations, CAD modelling, and experimental research.

The research project is a part of the Astrophysics at the University of Birmingham programme and Gravitational Wave Astronomy at the University of Birmingham, STFC Equipment Call 2018 that are funded by the UKRI Science and Technology Facilities Council.

Figures:

Figure 1: Picture of the experiment

Figure 2: Model of the fused silica 6D mass

Figure 3: Predicted improvement of the isolation

Selected publications:

A 6D interferometric inertial isolation system

For more information contact: Leonid Prokhorov, Sam Cooper, Amit Ubhi, Chiara Di Fronzo, Denis Martynov

Laboratory
CTN layout
CTN reference cavities

EPSRC Optical coatings

Optical coatings are formed by alternating layers of materials with different refractive indices and are utilised to reflect light from the mirror surfaces. Thermal motion of atoms inside optical coatings leads to the random phase modulation of light and noise in the readout channel of the gravitational-wave detectors, optical atomic clocks, and quantum optomechanical systems.

In collaboration with the UK National Quantum Hub in Sensors and Timing, we build an MIT-type experiment to measure properties of the key interferometric components: optical coatings, at 1550 nm. The key idea of the measurement is to resonate two beams in the same optical cavity and make all noises common to these beams, except for the thermal noises.

The research project "Coating thermal noise measurement with a multimode resonator" is funded by the UKRI Engineering and Physical Sciences Research Council as the New Investigator initiative.

Figures:

Figure 1: Laboratory

Figure 2: Optical layout of the experiment

Figure 3: Stability of reference cavities with current and future coatings

Selected publications:

Audio-band coating thermal noise measurement for Advanced LIGO with a multimode optical resonator.

For more information contact: Teng Zhang, Denis Martynov

Laboratory
Axion layout
Axion detection scheme

QTFP 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.

The research project is a part of the Quantum-enhanced Interferometry for New Physics programme that 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.

Figures:

Figure 1: Laboratory

Figure 2: Experimental layout

Figure 3: Expected sensitivity

Selected publications:

Quantum-enhanced interferometry for axion searches

For more information contact: Haixing Miao, Denis Martynov

SmarAct
HoQI
BOSEM

Position sensors

Operation of GW detectors at low temperature offers potentially great benefits, as well as major challenges. The GW community is exploring the Voyager concept, which has silicon test masses operating at 123 K. We work on expanding of our existing programme in suspension sensing and actuation hardware into cryogenic operation.

Improvements in the LIGO low-frequency band call for new position sensors with a low self-noise. We explore an application of interferometric readout to the LIGO suspensions and seismometers. Compact interferometers have the potential to improve the self-noise of existing LIGO position sensors by two orders of magnitude.

Figures:

Figure 1: SmarAct interferometric sensors

Figure 2: HoQI interferometric sensors

Figure 3: BOSEM sensors and actuators

Selected publications:

A compact, large-range interferometer for precision measurement and inertial sensing

Sensors and actuators for the Advanced LIGO mirror suspensions

For more information contact: Sam Cooper, Amit Ubhi, Denis Martynov

Amplifier: interaction
Amplifier: layout
Amplifier: sensitivity

EPSRC Quantum amplifiers

Quantum noise limits the sensitivity of modern precision measurements, such as observation of gravitational waves and dark matter searches. In order to advance precision measurements, we study quantum phase-insensitive amplifiers that have the potential to improve the performance of optical interferometers.

In our group, we build an active optical system that amplifies signal and noise asymmetrically and improves the signal-to-noise ratio compared to passive optical resonators. We embed a quantum filter with an active medium in the optical cavity to demonstrate the performance of the coupled cavity system with a particular gain.

The research project "Phase-insensitive amplifier for quantum measurements" is funded by the UKRI Engineering and Physical Sciences Research Council as the New Horizons initiative.

Figures:

Figure 1: Optomechanical interaction

Figure 2: Photo of the experiment

Figure 3: Quantum noise suppression

Selected publications:

Enhancing the bandwidth of gravitational-wave detectors with unstable optomechanical filters

Converting the signal-recycling cavity into an unstable optomechanical filter to enhance the detection bandwidth of gravitational-wave detectors

For more information contact: Joe Bentley, Jiri (George) Smetana, Amit Ubhi, Teng Zhang, Denis Martynov Haixing Miao

Group

John Bryant John Bryant
Research assistant
Sam Sam Cooper
Research staff
Seismic isolation
Artemiy Artemiy Dmitriev
Research staff
Optomechanics
Chiara Chiara Di Fronzo
PhD student
Seismic isolation
Alex Alex Gill
PhD student
Dark matter
David Hoyland David Hoyland
Research assistant
Riccardo Riccardo Maggiore
PhD student
Virgo detector
Denis Denis Martynov
Reader
Haixing Haixing Miao
Senior Lecturer
Leo Leonid Prokhorov
Research staff
Seismic isolation
George Jiri (George) Smetana
PhD student
Cryogenic silicon
Teng Teng Tzang
Research staff
Quantum optics
Amit Amit Ubhi
PhD student
Seismic isolation
Alberto Alberto Vecchio
Prof, Head of Institute

Join us

MSc positions:

Every year we offer two experimental projects for Birmingham Master students.

PhD positions:

Every year we offer 1-2 PhD positions to drive our experimental effort forward. The 2020-2021 PhD season is now closed.

Postdoc positions:

No openings at the moment.

Faculty positions:

No openings at the moment.

Send your questions about jobs to

Denis Martynov

Alberto Vecchio