Memory You Can Train ✎ express

Original: "Harnessing Environmental Memory with Reinforcement Learning in Open Quantum Systems"
arXiv:2601.01252 · 2026-01-03 · CC BY-NC-ND 4.0 · independent analysis · 1 min
Quantum systems, like people, perform better when they remember the past.

A quantum system, like a person in a noisy room, gradually loses the thread of conversation: its state dissipates into the surroundings. But sometimes, as if suddenly recalling an important thought, it can recover part of the lost information. Physicists call this phenomenon non-Markovian dynamics: the environment's memory of the system's past allows information to flow back.

Usually quantum systems 'forget' their past, but non-Markovian systems can 'remember'.

Scientists set out to amplify this effect by controlling a two-level system (the simplest quantum object, like an atom with two states) using reinforcement learning. This method is akin to training: a computer agent tries different sequences of control pulses and receives a reward for enhancing information return. Comparison with traditional optimal control showed that the standard approach yields only weak and sporadic bursts of return, while the trained agent synchronizes its actions with the environment's 'favorable memory windows' and achieves a significantly stronger effect.

The best result came from the SAC algorithm, while PPO gave slightly less but smoother pulses that are easier to implement experimentally. This means that the memory of a quantum system can be deliberately trained, turning it from a random occurrence into a working tool.

Information return is not a glitch but a resource that can be amplified severalfold.

Such an approach could help protect quantum computations from errors and create more resilient quantum devices.

The SAC algorithm, which performed best, was originally developed for teaching robots smooth movements, and now it helps control quantum systems.

Scientists
David DeutschErwin SchrödingerJohn Stewart BellLouis de BroglieLov GroverPaul Benioff
Concepts
Reinforcement Learning reservoir computing quantum computing resource optimization memory effect memory cell transfer learning agent Oberth effect Recurrent Neural Networks quantum temporal order memory active learning