Yale physi­cists find signs of a time crys­tal

Chemical Industry Digest - - Science Pages -

Yale physi­cists have un­cov­ered hints of a time crys­tal, a form of mat­ter that “ticks” when ex­posed to an elec­tro­mag­netic pulse. Time crys­tals, first iden­ti­fied in 2016, are dif­fer­ent. Their atoms spin pe­ri­od­i­cally, first in one di­rec­tion and then in an­other, as a pul­sat­ing force is used to flip them. That’s the “tick­ing.” In ad­di­tion, the tick­ing in a time crys­tal is locked at a par­tic­u­lar fre­quency, even when the pulse flips are im­per­fect.

Sci­en­tists said that un­der­stand­ing time crys­tals may lead to im­prove­ments in atomic clocks, gy­ro­scopes, and mag­ne­tome­ters, as well as aid in build­ing po­ten­tial quan­tum tech­nolo­gies. The U.S. De­part­ment of De­fense re­cently an­nounced a pro­gram to fund more re­search into time crys­tal sys­tems.

Yale’s new find­ings are de­scribed in a pair of stud­ies, one in Phys­i­cal Re­view Let­ters and the other in Phys­i­cal Re­view B. The stud­ies rep­re­sent the sec­ond known experiment ob­serv­ing a tell­tale sig­na­ture for a dis­crete time crys­tal (DTC) in a solid.

“We de­cided to try search­ing for the DTC sig­na­ture our­selves,” said Yale physics pro­fes­sor Sean Bar­rett, prin­ci­pal in­ves­ti­ga­tor for the two new stud­ies. The re­searchers used nu­clear mag­netic res­o­nance (NMR) to look for a DTC sig­na­ture and quickly found it. “Our work sug­gests that the sig­na­ture of a DTC could be found, in prin­ci­ple, by look­ing in a chil­dren’s crys­tal grow­ing kit,” Bar­rett added.

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