Time crystals are a strange phase of matter that emulates a crystalline structure in the fourth dimension, time, rather than in space, and was recently proposed by Frank Wilczek, Nobel Laureate in Physics, of the Massachusetts Institute of Technology (MIT)
Scientists from the University of Granada (UGR), Spain, and the University of Tübingen (UT), Germany have discovered a way to create time crystals, a new phase of matter that emulates a crystalline structure in the fourth dimension, time, rather than in space, from rare fluctuations in many-particle physical systems.
Time crystals are a new state of matter recently proposed by Frank Wilczek, Nobel Laureate in Physics, from the Massachusetts Institute of Technology (MIT).
In time crystals, whose existence was first proposed in 2012, the atoms repeat a pattern through the fourth dimension, time, unlike normal crystals (such as a diamond), whose atoms are arranged in a repetitive spatial structure. Thus, these new time crystals are characterised by an enduring periodic motion in time.
In this study, recently published in the journal Physical Review Letters of the American Physical Society—one of the most prestigious publications in the world in the field of physics—the UGR researchers demonstrate that certain dynamical phase transitions that appear in the fluctuations or rare events of many physical systems spontaneously break time-translation symmetry.
Researchers Rubén Hurtado Gutiérrez and Carlos Pérez Espigares and lecturer Pablo Hurtado, from the UGR’s Department of Electromagnetism and Matter Physics, in collaboration with researcher Federico Carollo of the UT, have proposed a new way to use this natural phenomenon to create time crystals.
To perform the simulations in this study, the scientists used PROTEUS, the supercomputer belonging to the «Carlos I» Institute of Theoretical and Computational Physics (iC1) of the UGR. PROTEUS (https://proteus.ugr.es/) is one of the most powerful general scientific calculation supercomputers in Spain, with a calculation capacity of more than 90 TeraFlops, more than 2,300 processing cores, 7.5 Terabytes of RAM, and 380 TeraBytes of data storage.
As Pablo Hurtado explains, the concept of time has challenged physicists and philosophers alike since ancient times. To paraphrase Saint Augustine of Hippo, “What, then is time? If no-one asks me, I know what it is. If I wish to explain it to he who asks, I do not know.”
“Einstein’s relativity taught us that time is somehow flexible and that it is inextricably linked to space in a whole that we know as SpaceTime. This Einsteinian unification is, however, partial, since time continues to be special in many ways”, observes the UGR researcher. Examples abound: we can move back and forth between any two points in space, yet we cannot visit the past; time has an arrow—pointing toward entropy increase—while space has no such arrow, etc. What’s more, time symmetries also exhibit interesting peculiarities”.
In their paper, the UGR scientists propose a hitherto unexplored route to building time crystals, based on the recent observation of spontaneous breaking of continuous time-translation symmetry in fluctuations of many-particle systems. These dynamic phase transitions (DPTs) appear in trajectory space when a physical system is conditioned to make a rare (or improbable) fluctuation in certain observables, such as the particle stream.
Using spectral analysis tools, the scientists unequivocally demonstrated the relationship between these DPTs and time crystals. Interestingly, these rare events can be made typical by transforming the microscopic dynamic of the particles, which can be interpreted in terms of the original dynamics supplemented by a smartexternal field. This enables the previously highly improbable temporal crystal behaviour to be exploited in a practical way.
Based on these observations, the researchers proposed a nonequilibrium fluid model that exhibits a time-crystal-like phase transition, breaking time-translation symmetry and displaying rigidity, robust coherent periodic motion, and long-range spatio-temporal order. In this paper, they also discuss how to create these time crystals in the laboratory from colloidal fluids in optical traps and under external packing fields generated with optical tweezers.
“These results are important because, at a fundamental level, they open an unexplored path to better understand time and its symmetries, while, on a practical level, they teach us new ways to create time crystals. This is especially relevant in fields such as metrology, for the design of more precise clocks, or in quantum computing, where time crystals can be used to simulate ground states or design quantum computers that are more resistant to decoherence, with the technological possibilities that this entails,” say the researchers.
Bibliography:
R. Hurtado-Gutiérrez, F. Carollo, C. Pérez-Espigares, and P.I. Hurtado (2020) ‘Building continuous time crystals from rare events’, Physical Review Letters 125, 160601. Online: https://doi.org/10.1103/PhysRevLett.125.160601. Also available at: https://arxiv.org/abs/1912.02733.
Media enquiries:
Pablo I. Hurtado
Department of Electromagnetism and Matter Physics
“Carlos I» Institute of Theoretical and Computational Physics
University of Granada
Tel.: +34 958 241000 ext. 20189
Email: phurtado@onsager.ugr.es
Website: http://ic1.ugr.es/phurtado
