(Fig.1) ↓ Time crystal just oscillates at different frequency or period (= 2T ) from the stimulator's frequency or period (= T ). No practical use.
Time crystal often becomes a hot topic in (overhyped) science news.
Contrary to such overhyped news, the time crystal has nothing to do with a perpetual motion machine, a time travel nor a deadend quantum computer ( this last-paragraph ).
Like ordinary matter, the time crystal obeys the law of energy conservation and thermodynamics ( this 6th-paragraph ). ← Time crystal is Not a perpetual motion machine.
Time crystal is a completely useless concept with No practical application.
This 2nd-last-paragraph says
"the current experiments with time crystals are far from any practical applications, whatever they might be."
Time crystal just means a system that is oscillating at a different frequency and period from the frequency or period of the external stimuli or driving force.
That's all. Time crystal has No physical importance nor any utility.
This p.2-left-2~3rd paragraphs say
"In 2012 Frank Wilczek proposed an idea of time crystals. He posed a question whether there exist systems which break spontaneously time translation symmetry. In other words if it is possible that a many-body system self-organizes in time and starts spontaneously to undergo a periodic motion.. It is already known that the original Wilczek idea cannot be realized."
"That time crystals are related to quantum self organization of motion of a many-body system that is periodically driven by an external force... the system prefers to move on its own and spontaneously switches to a periodic motion with a different period than a period of driving."
This-section below "Making a Time crystal" says
"In Lukin's project, the scientists used microwave pulses to flip the diamond defects' spins... the materials received external stimulation—lasers or microwave pulses—but they displayed a different period than that of their stimuli. In other words, they broke time symmetry spontaneously ( this 2~3rd-paragraphs )."
This 5~7th-paragraphs say
"scientists have indeed succeeded on a handful of occasions in demonstrating a potential time crystal. However, these were systems that -- unlike Wilczek's original idea -- are subjected to a temporal excitation with a specific periodicity, but then react with another period twice as long ( This 12th-paragraph )."
↑ This research paper ↓
p.1-right-2nd-paragraph says "We experimentally investigate the formation of discrete time-crystalline order in an ensemble of nitrogen vacancy (NV) spin impurities in diamond. Each NV center has an electronic S = 1 spin (= fictional electron spin itself is unobservable. Only light wave interacting with atomic energy levels was observable )"
"..from which we isolate an effective two level system by applying an external magnetic field. These isolated spin states can be optically initialized/detected and manipulated via microwave radiation"
p.2-right-2nd-paragraph says "We begin by applying continuous microwave driving... with a total period T = τ1 + τ2 and is repeated n times,"
p.2-right-3rd-paragraph says "we observe that the spin polarization P (= meaning just NV-center's two energy states ) alternates between positive and negative values, resulting in a subharmonic peak at ν = 1/2.. Remarkably, we find that a rigid 2T-periodic response is restored."
↑ In this experiment, they illuminated diamond's nitrogen-vacancy (=NV)-center by microwave with period of T, and NV-center oscillated between two energy levels with the period of 2T, which periodic difference they called "time crystal" that is just "unexpected spontaneous oscillation" with No practical use.
The 7th-10th, 12th paragraphs of this hyped news say
"From 2017 onward, scientists have indeed succeeded on a handful of occasions in demonstrating a potential time crystal. However, these were systems that—unlike Wilczek's original idea—are subjected to a temporal excitation with a specific periodicity, but then react with another period twice as long."
"A crystal that behaves periodically in time, although excitation is time-independent"
"physicists.. now designed a special crystal made of indium gallium arsenide, in which the nuclear spins act as a reservoir for the time crystal. The crystal is continuously illuminated so that a nuclear spin polarization forms through interaction with electron spins (= this experiment did Not see the unreal electron spin itself ). And it is precisely this nuclear spin polarization that then spontaneously generates oscillations, equivalent to a time crystal."
"The status of the experiments at the present time is that the crystal's lifetime is at least 40 minutes"
"These areas are also interesting, as chaotic behavior, which can be maintained over long periods of time (← No mention of practical use, which means the alleged tiime crystal showing only chaotic behavior is completely useless )"
↑ This experiment just continuously illuminated some material by laser light at extremely low temperature (< 20K ), and measured some periodic magnetic polarization change (= Not seeing electron spin ) of the material by the probe light based on classical Faraday rotation effect that just sees material magnetic direction, Not the unreal spin ( this p.2-Fig.1b ).
↑ That's all, this so-called time crystal is completely a meaningless, useless concept except for researchers wasting time to publish papers in academic journals.
This 2nd-last paragraph says
"the current experiments with time crystals are far from any practical applications, whatever they might be"
Time crystal is Not an occult quantum mechanical material violating laws of thermodynamics nor perpetual motion machine, so it's not worth researching on.
This lower paragraphs after "Making time crystal" say
"the (time crystal) materials received external stimulation—lasers or microwave pulses (= needing energy, so not perpetual motion machine ) — but they displayed a different period than that of their stimuli. In other words, they broke time symmetry spontaneously (= meaningless unphysical concept )."
↑ This means the (impractical) time crystal is just like some "broken windmill" that is rotating at unexpected chaotic frequency exposed to periodically-changing wind (= periods and frequencies of the broken windmill or time crystal and wind are different ).
This research paper (= p.3-right-2nd-paragraph ) also says
"Auto-oscillations occur in dissipative, nonlinear systems as the ENSS (= electron nuclear spin system or time crystal ), when a continuous source of incoming
energy (= laser light ) - in our case applied highly non-resonant - compensates for the energy losses (= Not perpetual machine ). The time evolution is
then determined by the intrinsic properties of the system
and is not affected from the outside. It may evolve as
periodic, chaotic, or even unpredictable (= chaotic oscillating time crystal is completely useless )".
↑ This experiment did Not conduct any quantum mechanical calculation based on spin nor quantum mechanical prediction. ← No proof of electron spin.
They just used the experimentally-observed electromagnetic values of mateial as free fitting parameters ( this p.2-right-1st-paragraph electron g-factor = 0.568 is completely different from electron spin g-factor = 2 = No evidence of electron spin ) with No quantum mechanical prediction.
This p.6-right-4th-paragraph uses free parameters fitted with experiments with No quantum mechanical prediction.
Time crystal (= Floquet ) is just a meaningless boring crystal contrary to the media-hype. Physicists (and journals ) never consider their practical application (except in hyped articles misleading laypersons ).
The 1-2nd, 5th, 8-9th, 11th, 14th, 18-19th paragraphs of this hyped news say
"Researchers have for the first time observed a time crystal (= meaningless useless crystal ) on a microscale semiconductor chip oscillating at a rate of several billion times per second, unveiling exceptionally high non-linear dynamics in the GHz range."
"The results of the experiment, published in Science, establish a firm connection between formerly uncorrelated areas of non-linear exciton-polariton dynamics and coherent optomechanics at GHz frequencies, say researchers from the Paul-Drude-Institute for Solid State Electronics (PDI) in Berlin, Germany, and the Argentina-based Centro Atómico Bariloche and Instituto Balseiro (CAB-IB)."
"When the CAB-IB team directed a time-independent (i.e. continuous) laser at the sample, they observed that the particles (= fictional particles explained later ) it contained began to oscillate at GHz frequencies—a billion times per second."
"In accordance with their theory, the researchers found that on further increasing the laser power, the particles vibrated at exactly half the frequency of the mechanical vibrations."
"This behavior can be interpreted as different manifestations of a time crystal (= time crystal is a useless vague thing just oscillating at different frequencies or periods ),"
"Since Nobel-Prize-winning physicist Frank Wilczek first proposed his theory over a decade ago, researchers have been on the search for elusive "time crystals"—many-body systems composed of (fictional) particles and quasiparticles like excitons, photons, and polaritons that, in their most stable quantum state, vary periodically in time."
"And while time crystals have now been observed on several occasions in systems driven out of equilibrium, much about them remains undetermined: their internal dynamics are largely beyond the current understanding of scientists (= quantum mechanical failed to explain it ), and their potential uses have remained in the realm of theory rather than practice (= time crystal is just an impractical theoretical concept )."
"Due to the polariton-enhanced coupling between GHz phonons (= fictional quasiparticles ) and near-infrared photons, the results have the potential (= just speculation ) for applications in (quantum) conversion between microwave and optical frequencies"
"Semiconductor-based non-linear optoelectronic systems—devices that can convert light energy to electrical energy or vice versa—are drawing particular attention for their potential (= still unrealized ) applications in on-chip photonics. But they are notoriously difficult to study due to the many-body complexes (such as time crystals)."
↑ This research just shone light wave on some material that was transiently excited to oscillate at various different frequencies, which is the definition of "time crystal", and tried to explain it by fictional quasiparticle model. No practical application.
↑ This research paper ( this ↓ )
p.1-abstract-last says "These results establish microcavity polaritons (= unreal quasiparticle ) as a platform for the investigation of time-broken symmetry in non-hermitian systems (= No mention of practical use )"
p.1-right-1st-paragraph says "Our solid-state CTC (= continuous time crystal ) system is based on polaritons, quasiparticles resulting from the strong coupling between excitons (= this is also a fictional quasiparticle ) and photons in a semiconductor intracavity trap"
p.2-Figure 1 says "cw laser power Pcw.. (B) Spectrally-resolved photoluminescence images ..
Due to linear polarized pumping and carrier relaxation, at low powers, exciton (= fictional quasiparticle ) spin-up and spin-down populations in the reservoir are balanced, leading
to a degenerate polariton (= quasiparticle ) ground state.
Increasing Pcw breaks time translation symmetry, initiating spontaneous Larmor precession
(continuous time crystal), indicated by pseudospin (= fake spin ) state splitting
"
p.3-Figure 2-(A) says Up-arrows mark peaks related to period-doubling (= by illuminating the material by some laser light, it emitted light with frequencies and periods different from the basic frequency ν0, which they considered as the sign of time crystal ).
p.4-Figure.3 artificially chose simulation parameters, which was Not a quantum mechanical prediction.
p.6-right says "Fed by a fully incoherent exciton bath, this system exhibits continuous time crystalline behavior involving the spinor of the trapped condensate’s ground state and its coupling to a dynamic exciton reservoir. Period-doubling occurs without any external time-dependent harmonic driving, referenced to mechanical coherent vibrations that are self-induced by the polariton fluid. These self-induced mechanics stabilize and lock the frequency of the time crystal, acting as an internal clock"
↑ As a result, this research just illuminated the material with laser light, and the excited material emitted light with various frequencies and periods (= time crystal ? ), about which they tried to use fictional quasiparticle model, which obstructs the clarification of real underlying mechanisms.
This time crystal is also meaningless, useless concept intended only for publishing papers in journals that need the (deadend) quantum computer as a fake scientific target.
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