Experiment to ‘reverse time’ using a quantum computer challenges the second law of thermodynamics

A group of enterprising quantum physicists have questioned the perception that time’s arrow runs only in one direction, in an experiment using qubits to challenge the second law of thermodynamics.

Researchers from across the globe — including institutes in Moscow, the US and Switzerland — have collaborated to wind the state of a quantum computer back into the past by a fraction of a second. They also calculated the probability that an electron in empty space will travel back into its recent past.

The study is part of a series of papers that explore the possibility of violating the second law of thermodynamics and the closely linked notion that time’s arrow points only from the past to the future.

Gordey Lesovik, head of the Laboratory of the Physics of Quantum Information Technology at the Moscow Institute of Physics and lead author of the paper, states: “ We began by describing a so-called local perpetual motion machine of the second kind. Then, in December, we published a paper that discusses the violation of the second law via a device called Maxwell’s demon.