A new method of identifying gravitational wave signals using quantum
computing could provide a valuable new tool for future astrophysicists.
A team from the University of Glasgow's School of Physics & Astronomy
have developed a quantum algorithm to drastically cut down the time it takes
to match gravitational wave signals against a vast databank of templates.
This process, known as matched filtering, is part of the methodology that
underpins some of the gravitational wave signal discoveries from detectors
like the Laser Interferometer Gravitational Observatory (LIGO) in America
and Virgo in Italy.
Those detectors, the most sensitive sensors ever created, pick up the faint
ripples in spacetime caused by massive astronomical events like the
collision and merger of black holes.
Matched filtering allows computers to pick gravitational wave signals out of
the noise of the data collected by the detector. It works by sifting through
the data, searching for a signal which matches one out of potentially
hundreds of trillions of templates—pieces of pre-created data which are
likely to correlate with a genuine gravitational wave signal.
While the process has enabled numerous gravitational wave detections since
LIGO picked up its first signal in September 2015, it is time-consuming and
resource-intensive.
In a new paper published in the journal Physical Review Research, the team
describe how the process could be greatly accelerated by a quantum computing
technique called Grover's algorithm.
Grover's algorithm, developed by computer scientist Lov Grover in 1996,
harnesses the unusual capabilities and applications of quantum theory to
make the process of searching through databases much faster.
While quantum computers capable of processing data using Grover's algorithm
are still a developing technology, conventional computers are capable of
modeling their behavior, allowing researchers to develop techniques which
can be adopted when the technology has matured and quantum computers are
readily available.
The Glasgow team are the first to adapt Grover's algorithm for the purposes
of gravitational wave search. In the paper, they demonstrate how they have
applied it to gravitational wave searches through software they developed
using the Python programming language and Qiskit, a tool for simulating
quantum computing processes.
The system the team developed is capable of a speed-up in the number of
operations proportional to the square-root of the number of templates.
Current quantum processors are much slower at performing basic operations
than classical computers, but as the technology develops, their performance
is expected to improve. This reduction in the number of calculations would
translate into a speed up in time. In the best case that means that, for
example, if a search using classical computing would take a year, the same
search could take as little as a week with their quantum algorithm.
Dr. Scarlett Gao, from the University's School of Physics & Astronomy,
is one of the lead authors of the paper. Dr. Gao said: "Matched filtering is
a problem that Grover's algorithm seems well-placed to help solve, and we've
been able to develop a system which shows that quantum computing could have
valuable applications in gravitational wave astronomy.
"My co-author and I were Ph.D. students when we began this work, and we're
lucky to have had access to the support of some of the UK's leading quantum
computing and gravitational wave researchers during the process of
developing this software.
"While we've concentrated on one type of search in this paper, it's possible
that it could also be adapted for other processes which, like this one,
don't require the database to be loaded into quantum random access memory."
Fergus Hayes, a Ph.D. student in the School of Physics & Astronomy, is
co-lead author of the paper. He added: "Researchers here in Glasgow have
been working on gravitational wave physics for more than 50 years, and work
in our Institute for Gravitational Research helped to underpin the
development and data analysis sides of LIGO.
"The cross-disciplinary work that Dr. Gao and I led has demonstrated the
potential of quantum computing in matched filtering. As quantum computers
develop in the coming years, it's possible that processes like these could
be used in future gravitational wave detectors. It's an exciting prospect,
and we're looking forward to developing this initial proof of concept in the
future."
The paper was co-written by Dr. Sarah Croke, Dr. Christopher Messenger and
Dr. John Veitch, all from the University of Glasgow's School of Physics
& Astronomy.
The team's paper, titled "A quantum algorithm for gravitational wave matched
filtering," is published in Physical Review Research.
Reference:
A quantum algorithm for gravitational wave matched filtering,
arXiv:2109.01535 [quant-ph]
arxiv.org/abs/2109.01535
Tags:
Physics