Scientists have demonstrated a way to simulate the reversal of time in certain quantum systems, opening up new possibilities for energy collection.
A novel approach enables the apparent reversal of time’s direction in quantum setups, which might eventually aid in powering quantum batteries.
In the observable universe, events unfold in a single forward direction, aligning with what seems like an irreversible flow of time. However, many fundamental physical principles function equally well regardless of time’s direction.
Experts offer various reasons for this mismatch between observed time progression and the symmetry in equations. One key idea is the second law of thermodynamics, which states that disorder tends to increase over time, establishing a favored temporal path.
In quantum mechanics, time’s arrow is conceptualized differently. Quantum events can proceed in either direction, similar to classical laws, but researchers define a temporal direction by matching observations of a quantum system against predictions of its evolution. When these align in a specific way, the system appears to advance forward in time.
Luis Pedro García-Pintos from Los Alamos National Laboratory in New Mexico, along with his team, has devised a method to replicate the indicators of reversed time. They achieve this by anticipating and counteracting the alterations that observations impose on a quantum system, creating the illusion of backward progression to an external viewer.
The researchers apply targeted fields and controls to offset the impacts of measurements. If a measurement would shift the system in one direction, they adjust it to move oppositely. This intervention generates paths that better match a backward rather than forward process.
For instance, the group proposes manipulating time’s arrow in a qubit—a basic unit in quantum computing—by indirectly assessing a trait like its spin to preserve the fragile quantum state. This allows ongoing monitoring as the system evolves. The data then informs adjustments via microwave pulses to alter the perceived time direction.
This method might enable energy capture from quantum systems requiring observations, according to García-Pintos, with potential uses in quantum batteries or small-scale quantum motors. Measurements inherently add energy to quantum systems, and the precise controls for simulating time reversal can redirect this energy for practical purposes.
Mauro Paternostro from Queen’s University Belfast in the UK describes the concept as innovative, though tailored to specific configurations that may not broadly apply to actual quantum systems.
He emphasizes that the approach respects the second law of thermodynamics, as energy must be invested to organize the system and lower its disorder, akin to expending effort to tidy a cluttered space.
