AC Josephson effect between two superfluid time crystals
13 Mar 2020
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Autti Samuli
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Heikkinen Petri J.
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Mäkinen Jere T.
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Volovik Grigori E.
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Zavjalov Vladislav V.
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Eltsov Vladimir B.
Quantum time crystals are systems characterised by spontaneously emerging
periodic order in the time domain. A range of such phases has been reported...The concept has even been discussed in popular literature, and deservedly so:
while the first speculation on a phase of broken time translation symmetry did
not use the name "time crystal", it was later adopted from 1980's popular
culture. For the physics community, however, the ultimate qualification of a
new concept is its ability to provide predictions and insight. Confirming that
time crystals manifest the basic dynamics of quantum mechanics is a necessary
step in that direction. We study two adjacent quantum time crystals
experimentally. The time crystals, realised by two magnon condensates in
superfluid $^3$He-B, exchange magnons leading to opposite-phase oscillations in
their populations -- AC Josephson effect -- while the defining periodic motion
remains phase coherent throughout the experiment.(read more)