Onward to the future. Now back to the past, please.
You’re probably already familiar with the strange behaviors of time in the realm of quantum mechanics, such as time reversal: Time doesn’t go backward in our daily lives, but temporal symmetry ensures that there’s no such thing as an arrow of time inexorably going from the past to the future when we reach atomic dimensions.
Now, a trio of physicists at Los Alamos National Laboratory in the US has developed control protocols for quantum experiments that generate processes more consistent with time flowing backward, to the past, rather than forward, to the future.
The protocols—techniques for controlling systems made up of subatomic particles—modify the arrow of time in a quantum system, stretching, blurring, and even reversing the concept of time moving in a single direction.
It’s quite a scientific and philosophical curiosity, but the work also opens up possibilities for extracting energy from systems governed by quantum mechanics – yes, that’s right, quantum batteries could be recharged by making time run backward.
In addition to
Alternative energy sources
Adjustments to the time arrow
A quantum system—think of a row of qubits in a quantum computer, for example—is governed by the laws of quantum mechanics. The control protocols created by the team can be adjusted to prevent the arrow of time from appearing in such a system or even reverse its direction, that is, make time appear to flow backward.
To demonstrate the practical application of their controls, the team used the protocols to design a measurement mechanism that extracts energy from the measurements performed on the system itself. Unlike classical physics, where measuring something has little influence on the observed phenomenon, in quantum physics measurements alter the state of the system, inducing an arrow of time.
The team designed a sequence of fields and pulses capable of emulating the effects of the measurements. Using this device in a feedback process, it becomes possible to cancel, amplify, or overcompensate for the disturbances induced by the measurements, generating new trajectories of the event sequences.
It is these trajectories, with their completely anomalous sequences, that are consistent with stretched, blurred, or even inverted arrows of time.
Batteries and quantum demons
This ability to modify the flow of energy entering and leaving a quantum system could be useful in practical terms, including powering a continuous measurement mechanism. In other words, the mechanism will extract energy from the measurement process itself.
Quantum measurements, therefore, can function as a thermodynamic resource from which energy can be extracted – for example, to power another process or to store that energy in a quantum battery.
The team now intends to conduct an experimental demonstration of the use of their controls using superconducting qubits, eventually creating a platform that allows for fast and highly efficient feedback. Do you know what that means? That essentially it will become possible to control a Maxwell’s demon, that strange little guy who loves to play with the laws of thermodynamics.
Source: www.inovacaotecnologica.com.br
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