Time crystals leave the lab
Time crystals that persist indefinitely at room temperature could have applications in precision timekeeping

Date:
February 14, 2022
Source:
University of California - Riverside
Summary:
Cutting-edge research has observed time crystals in a system that is
not isolated from its ambient environment. This major achievement
brings scientists one step closer to developing time crystals for
use in real- world applications.



FULL STORY ==========================================================================
We have all seen crystals, whether a simple grain of salt or sugar, or
an elaborate and beautiful amethyst. These crystals are made of atoms or molecules repeating in a symmetrical three-dimensional pattern called
a lattice, in which atoms occupy specific points in space. By forming
a periodic lattice, carbon atoms in a diamond, for example, break the
symmetry of the space they sit in.

Physicists call this "breaking symmetry."

========================================================================== Scientists have recently discovered that a similar effect can be witnessed
in time. Symmetry breaking, as the name suggests, can arise only where
some sort of symmetry exists. In the time domain, a cyclically changing
force or energy source naturally produces a temporal pattern.

Breaking of the symmetry occurs when a system driven by such a force
faces a de'ja` vu moment, but not with the same period as that of the
force. 'Time crystals' have in the past decade been pursued as a new
phase of matter, and more recently observed under elaborate experimental conditions in isolated systems. These experiments require extremely low temperatures or other rigorous conditions to minimize undesired external influences, called noise.

In order for scientists to learn more about time crystals and employ
their potential in technology, they need to find ways to produce time crystalline states and keep them stable outside the laboratory.

Cutting-edge research led by UC Riverside and published this week
inNature Communicationshas now observed time crystals in a system that
is not isolated from its ambient environment. This major achievement
brings scientists one step closer to developing time crystals for use
in real-world applications.

"When your experimental system has energy exchange with its surroundings, dissipation and noise work hand-in-hand to destroy the temporal order,"
said lead author Hossein Taheri, an assistant research professor
of electrical and computer engineering in UC Riverside's Marlan and
Rosemary Bourns College of Engineering. "In our photonic platform,
the system strikes a balance between gain and loss to create and
preserve time crystals." The all-optical time crystal is realized
using a disk-shaped magnesium fluoride glass resonator one millimeter
in diameter. When bombarded by two laser beams, the researchers observed subharmonic spikes, or frequency tones between the two laser beams, that indicated breaking of temporal symmetry and creation of time crystals.

The UCR-led team utilized a technique called self-injection locking of the
two lasers to the resonator to achieve robustness against environmental effects.

Signatures of the temporally repeating state of this system can readily
be measured in the frequency domain. The proposed platform therefore
simplifies the study of this new phase of matter.

Without the need for a low temperature, the system can be moved outside
a complex lab for field applications. One such application could be
highly accurate measurements of time. Because frequency and time are mathematical inverses of each other, accuracy in measuring frequency
enables accurate time measurement.

"We hope that this photonic system can be utilized in compact and
lightweight radiofrequency sources with superior stability as well as
in precision timekeeping," said Taheri.

The open-access Nature Communications paper, "All-optical dissipative
discrete time crystals," is available here. Taheri was joined in the
research by Andrey B. Matsko at NASA's Jet Propulsion Laboratory, Lute
Maleki at OEwaves Inc. in Pasadena, Calif., and Krzysztof Sacha at
Jagiellonian University in Poland.

========================================================================== Story Source: Materials provided by
University_of_California_-_Riverside. Original written by Holly
Ober. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Hossein Taheri, Andrey B. Matsko, Lute Maleki, Krzysztof Sacha. All-
optical dissipative discrete time crystals. Nature Communications,
2022; 13 (1) DOI: 10.1038/s41467-022-28462-x ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220214183323.htm

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