Physicists at Yale University have devised a way to give
scientists greater control in the volatile realm of quantum mechanics by
letting them observe quantum data without disruption —an important step
towards building a working quantum computer.
A report on SciTechDaily
said the scientists developed a new, non-destructive measurement system
for observing, tracking and documenting all changes in a qubit’s state,
preserving the qubit’s informational value.
“Our experiment is a dress rehearsal for a type of process essential for
quantum computing,” said Michel Devoret, the Frederick William Beinecke
Professor of Applied Physics & Physics at Yale.
“What this experiment really allows is an active understanding of
quantum mechanics. It’s one thing to stare at a theoretical formula and
it’s another thing to be able to control a real quantum object,” he
added.
Devoret is also the principal investigator of research published Jan. 11 in the journal Science.
The SciTechDaily report said this could greatly improves the prospects
of quantum computing, with quantum computers being envisioned to be
exponentially faster than today's most powerful computers.
Other authors of the paper include S. Shankar, M. Mirrahimi, F.
Schackert, K. Geerlings, T. Brecht, K.M. Sliwa, B. Abdo, L. Frunzio,
S.M. Girvin, and R.J. Schoelkopf.
Support for
the research was provided by the National Science Foundation, the United
States Army Research Office, the Intelligence Advanced Research
Projects Activity, the Agence National de Recherche, and the College de
France.
Quantum systems
In quantum systems, microscopic units called qubits represent
information, with qubits assuming either of two states 0 or 1, or both
simultaneously.
While it is important to
recognize and track their state for quantum computing, the act of
monitoring them usually damages their information content.
But now, Yale physicists drew up a new, non-destructive measurement
system for observing, tracking and documenting all changes in a qubit’s
state, preserving the qubit’s informational value.
"In principle, the scientists said, this should allow them to monitor
the qubit’s state in order to correct for random errors," SciTechDaily
said.
“As long as you know what error process
has occurred, you can correct. And then everything’s fine. You can
basically undo the errors,” Devoret said.
Michael Hatridge, a postdoctoral associate in physics at Yale and lead
author of the Science paper, added this is the key - “the ability to
talk to the qubit and hear what it’s telling you.”
“A major problem with quantum computing is the finite lifetime of
information stored in the qubits, which steadily decays and which must
be corrected. We now know that it is possible to do this correction by
feedback involving a continuous measurement. Our work advances the
prospects of large-scale quantum computers by opening the door to
continuous measurement-based quantum feedback,” he said.
The Yale physicists have successfully measured one qubit, but now the challenge is to measure and control many at once.
For now, the team is developing ultra-fast digital electronics for this purpose.
“We are on the threshold between the ability to measure and control one or two qubits, and many,” Hatridge said. — TJD, GMA News
source: gmanetwork.com
