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Quantum
transport in a chain of resonators obeying space reflection and time reversal
symmetries. Credit: Vasil Saroka |
Physicists from Exeter and Trondheim have devised a theory that explains how to use space reflection and time reversal symmetries to govern transport and correlations within quantum materials.
Two
theoretical physicists from the University of Exeter (UK) and the Norwegian
University of Science and Technology (Trondheim, Norway) have developed a
quantum theory that describes a chain of quantum resonators that satisfy space
reflection and time reversal symmetry. They've demonstrated how the various
quantum phases of such chains are linked to interesting events, which could be
important in the development of future quantum devices that rely on strong
correlations.
The contrast between open and closed systems is a common one in physics. Because closed systems are isolated from the outside world, energy is conserved because there is nowhere for it to escape. Open systems are connected to the outside world and are subject to energy gains and losses as a result of exchanges with the environment. There is a third case to consider. When the energy going in and out of the system is carefully balanced, the system enters a state that is halfway between open and closed. When the system obeys a combined symmetry of space and time, that is, when
- switching left and right and
- changing the arrow of time leave the system basically intact, the system is said to be in equilibrium.
Downing
and Saroka describe the phases of a quantum chain of resonators that satisfy
space reflection and time reversal symmetry in their recent paper. A trivial
phase (associated by intuitive physics) and a nontrivial phase are the two main
phases of interest (marked with surprising physics). A unique point marks the
transition between these two eras. The researchers discovered the locations of
these unique points for a chain of any number of resonators, revealing how
quantum systems obeying these symmetries scale up. The nontrivial phase, in
particular, allows for unusual transport effects and strong quantum
correlations, which can be exploited to regulate the behavior and propagation
of light on nanoscopic length scales.
This
theoretical study could help with the generation, manipulation, and control of
light in low-dimensional quantum materials, with the goal of developing
light-based systems that use photons, or light particles, as workhorses at
sizes as small as one billionth of a metre.
"Our
study on parity-time symmetry in open quantum systems further underscores how
symmetry underpins our understanding of the physical world, and how we can
profit from it," said Charles Downing of the University of Exeter.
"We hope that our theoretical work on parity-time symmetry might motivate additional experimental research in this intriguing field of physics," said Vasil Saroka of the Norwegian University of Science and Technology.
Originally Published Here.
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