Physicists long believed time was a basic feature of the universe. But it may just emerge from cosmic information.
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Random driving on a 78-qubit processor reveals controllable prethermal plateau
Time-dependent driving has become a powerful tool for creating novel nonequilibrium phases such as discrete time crystals and Floquet topological phases, which do not exist in static systems. Breaking continuous time-translation symmetry typically leads to the outcome that driven quantum systems absorb energy and eventually heat up toward a featureless infinite-temperature state, where coherent structure is lost.
Understanding how fast this heating process occurs and whether it can be controlled has become a challenge in nonequilibrium physics. High-frequency periodic driving is known to delay heating, but much less is known about heating dynamics under more general, non-periodic driving protocols.
Laser Light Rewrites Magnetism in Breakthrough Quantum Material
Researchers at the University of Basel and ETH Zurich have found a way to flip the magnetic polarity of an unusual ferromagnet using a laser beam. If the approach can be refined and scaled, it points toward electronic components that could be reconfigured with light instead of being permanently fixed.
A ferromagnet acts like it has a built-in internal agreement. Inside the material, enormous numbers of electrons behave like tiny bar magnets because of their spins. When those spins line up, their individual magnetic fields add together, producing the familiar strength that makes a compass needle settle in a direction or lets a refrigerator magnet cling to a door.
That orderly alignment is not automatic, because heat constantly shakes the system. Ferromagnetism appears only when the interactions that encourage alignment win out over thermal motion, which happens below a critical temperature (often called the Curie temperature).
