Exploring quantum aspects of gravitational-wave detectors

Lead Research Organisation: University of Birmingham
Department Name: School of Physics and Astronomy

Abstract

Einstein's general theory of relativity is currently our fundamental theory about spacetime and matter. It is an elegant theory and explains the observed astronomical phenomena very well. It also predicts the existence of gravitational waves, which are ripples in spacetime propagating at the speed of light. By detecting gravitational waves created by cosmic objects such as black holes, we aim to open a new window on the Universe through gravitational-wave astronomy. The efforts for detecting gravitational waves started almost half a century ago and have turned out to be one of the most challenging endeavours in experimental science, because the amplitudes of the expected waves are extremely small. The state-of-the-art approach for gravitational wave detection is using kilometre-scale laser interferometer with tens-of-kilograms mirrors as test masses. Several such interferometric detectors have been built around the world. Their sensitivity is so great that, even though they use macroscopic components, their performance is affected and limited by tiny quantum effects. The proposed research is aiming at better understanding the various quantum aspects of gravitational wave detectors. On the one hand, this leads to new approaches to overcome the quantum-limits of current detectors, which is an essential step for realizing the ultimate goal of gravitational-wave astronomy. On the other hand, it opens up the possibility to explore quantum behaviours of macroscopic objects in a new regime.

Publications

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Branford D (2018) Fundamental Quantum Limits of Multicarrier Optomechanical Sensors. in Physical review letters

 
Description Birmingham Fellow (permanent faculty position)
Amount £0 (GBP)
Organisation University of Birmingham 
Sector Academic/University
Country United Kingdom
Start 03/2016 
 
Description Enhancing gravitational wave detector sensitivity and bandwidth for astronomy
Amount $1,097,000 (AUD)
Funding ID DP170104424 
Organisation Australian Research Council 
Sector Public
Country Australia
Start 01/2017 
End 12/2021
 
Description The Royal Society International Exchanges Scheme
Amount £12,000 (GBP)
Funding ID IEC\NSFC\170345 
Organisation The Royal Society 
Sector Academic/University
Country United Kingdom
Start 03/2018 
End 03/2019
 
Description LIGO Scientific Collaboration 
Organisation LIGO Scientific Collaboration
Country United States 
Sector Academic/University 
PI Contribution I have been working on different approaches to improving quantum-limited sensitivity of advanced gravitational-wave detectors. My research outcome provides direct inputs to current R&D of techniques for both near-term upgrade of current detectors and building the next-generation gravitational-wave observatories.
Collaborator Contribution They provide complimentary sets of expertise to my research. For example, my theoretical analysis is focusing on experimental setups that my partners are working on, and their feedback is essential to my research.
Impact Please refer to the publications with LIGO Scientific Collaboration as the author list. The most significant output is the recent breakthrough discovery of gravitational waves from merging of binary black holes.
 
Description A unified framework for improving quantum-limited detector sensitivity 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact This is a talk that I gave at Amaldi 12 Gravitational-Wave Conference held at Pasadena California. This is one of the largest international conference on gravity-related research. I talked about a unified framework for improving quantum-limited sensitivity of gravitational-wave detectors. This is based upon the recent breakthrough understanding of fundamental quantum limit of detector sensitivity. The audiences showed great interests to the topic, and asked many detailed questions after the talk.
Year(s) Of Engagement Activity 2017
URL http://amaldi12.org
 
Description An interview by China Global Television Network 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact On March 14, 2017, I was interviewed by China Global Television Network (formerly CCTV International) to comment on Steven Hawking's life and legacy.
Year(s) Of Engagement Activity 2017
URL https://www.youtube.com/watch?v=FzAvyDiFalw
 
Description CCTV America Interview 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact I was interviewed by CCTV America to report on the breakthrough discovery of gravitational waves by LIGO.
Year(s) Of Engagement Activity 2016
URL https://www.youtube.com/watch?v=lrVfHStGVlU
 
Description Conditional Frequency Dependent Squeezing via EPR Entanglement 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact This is a talk given at the LSC-VIRGO Collaboration September Meeting in Geneva, where I presented an new idea of improving gravitational-wave detector sensitivity based upon quantum entanglement.
Year(s) Of Engagement Activity 2017
 
Description Conditional frequency dependent squeezing via EPR entanglement 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact This is a talk that I gave at the largest annual meeting of LIGO Scientific Collaboration and VIRGO Collaboration which was held at CERN Geneva. I talked about a new idea of improving the quantum-limited sensitivity of advanced gravitational-wave detectors by using the famous Einstein-Podolsky-Rosen quantum entanglement.
Year(s) Of Engagement Activity 2017
URL http://www.et-gw.eu/index.php/news/119-lsc-virgo-meeting-2017
 
Description Design Concepts for High-Frequency Gravitational Wave Detectors 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact This is an invited talk at the KITPC Workshop on Gravitational Waves 2018 in Beijing. The audiences are international colleagues in the gravitational-wave community.
Year(s) Of Engagement Activity 2018
URL http://2018gw.csp.escience.cn/
 
Description Fundamental Quantum Limit of Gravitational-wave Detectors 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Other audiences
Results and Impact This is a talk presented in the 9th Nottingham Symposium on Quantum Systems held by the University of Nottingham. The audiences are colleagues from the University of Nottingham.
Year(s) Of Engagement Activity 2017
 
Description Fundamental quantum limit of gravitational-wave detectors 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact This is an invited talk that I gave at 9th Nottingham Symposium on Quantum Systems which was held in University of Nottingham.
Year(s) Of Engagement Activity 2017
 
Description GWADW 2016 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact This is a workshop on advanced gravitational-wave detectors. I have been actively involved in group discussions about techniques for improving quantum-limited detector sensitivity.
Year(s) Of Engagement Activity 2016
URL https://agenda.infn.it/conferenceDisplay.py?confId=10512
 
Description Gravitational-wave Astronomy and Quantum-limited Instruments 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact This is a talk given at Tianqin Research Centre in the Sun Yat-Sen University. I gave an overview of the research in our Insititute for Gravitational-Wave Astronomy at Birmingham.
Year(s) Of Engagement Activity 2017
 
Description Gravitational-wave astronomy and quantum-limited instruments 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact This is a talk that I gave at the Tianqin Research Centre in the Sun Yat-Sen University (SYSU). It provided an overview of research activities of Birmingham Institute of Gravitational Wave Astronomy, and aimed at establishing collaborations between Birmingham and SYSU which hosts a strong gravitational-wave group.
Year(s) Of Engagement Activity 2017
 
Description Interview for the breakthrough discovery of merging binary neutron stars 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Media (as a channel to the public)
Results and Impact I was interviewed by the media of University of Birmingham to comment on the breakthrough discovery of binary neutron stars, which marks the dawn of multi-messenger astronomy.
Year(s) Of Engagement Activity 2017
URL https://www.birmingham.ac.uk/news/latest/2017/10/Scientists-celebrate-first-direct-observation-of-co...
 
Description LVC Meeting September 2016 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact I gave a talk to report on the fundamental quantum limit to the sensitivity of gravitational-wave detectors. This is one of the key topics proposed in this funding award.
Year(s) Of Engagement Activity 2016
URL http://einstein.astro.gla.ac.uk/lvc2016/
 
Description LVC meeting September 2016 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact I gave a tutorial on future advanced gravitational-wave detectors to postgraduate students. This is a part of the LIGO Academic Affairs Council (LAAC) tutorials to inform students in the collaboration of advanced topics.
Year(s) Of Engagement Activity 2016
URL http://einstein.astro.gla.ac.uk/lvc2016/
 
Description Laser Interferometric Gravitational Wave Detectors-Where Gravity Meets Quantum 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact I was invited to give a seminar on quantum aspects of laser interferometric gravitational wave detectors at the Quantum Engineering Technology Labs in the University of Bristol.
Year(s) Of Engagement Activity 2019
 
Description Prospects of Improving Detector at Low Frequencies and High Frequencies 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact This is an invited talk given at the LSC-VIRGO Collaboration March Meeting in Sonoma State University, which is the largest annual meeting of the collaboration.
Year(s) Of Engagement Activity 2018
URL http://ligo.sonoma.edu/
 
Description Quantum Limits of Laser Interferometric Gravitational Wave Detectors 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact This is a seminar given at Tsinghua State Key Laboratory of Low-Dimensional Quantum Physics.
Year(s) Of Engagement Activity 2018
 
Description Quantum Techniques in Laser interferometric Gravitational Wave Detectors 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Other audiences
Results and Impact This is a talk given at the Workshop on Quantum Sensors for Fundamental Physics held in Oxford. The audiences are colleagues from both quantum measurement and particle physics community.
Year(s) Of Engagement Activity 2018
 
Description Towards the Design of Gravitational-wave Detectors for Neutron-star Physics 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact This is a seminar given at Tsinghua University Centre for Astrophysics (THCA), where I reported a new design of gravitational-wave detector for probing neutron star physics.
Year(s) Of Engagement Activity 2017
 
Description Towards the design of gravitational-wave detectors for neutron-star physics 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact This is a seminar that I gave at the Tsinghua University Centre for Astrophysics (THCA). It was about a new conceptual design of a gravitational-wave detector for probing new physics during the merger phase of binary neutron stars.
Year(s) Of Engagement Activity 2017