Quantum Observation Causes Energy Flow Against Direction Of Current, Study Shows

A group of researchers from the Max Planck Institute PMSD in collaboration with BCCMS centre in Bremen have made a unique finding in quantum science.

In a classic thermodynamic system, heat flows from a hot body to a cold one. This holds good for all forms of energy like electricity too, from the higher voltage to the lower one. The same happens in a quantum systems too, but the team found an anomaly to this fundamental principle of physics, wherein the introduction of an observer in the quantum system reverses the flow of energy and particles.

The study published in npj Quantum Materials, deals with the principle known as the observer effect. This is where a quantum system changes or undergoes modifications when an observer is introduced. This means that an object merely by observing a quantum system changes its state. The study of this effect has revealed some important anomalies in thermodynamic laws.

In all macroscopic systems, such as the flow of water and air, the flow takes place from a region of high concentration to a region of low concentration, from the upper to the lower part of the system. However, in quantum systems, "the process of observation changes the state of the system, and this makes it more likely that the current will be made to flow in one direction or another," says professor Ángel Rubio, who led the team, in a phys.org report.

The team confirmed that there were no disruptions to existing physics laws because of the discovery. The change in quantum direction is attributed to the introduction of the observer, which in the system acts as an obstacle.

"An infringement of any fundamental theorem of physics nor is energy created out of nothing. What happens is that inserting an observer into the system acts as an obstacle, as if you were to close off the channel in a pipeline through which the water is flowing. Obviously, if the load starts to build up, it would end up going in the opposite direction. In other words, the observer projects the state of the system onto a state that transmits the current or energy in opposite directions," Rubio said.

What was initially mistaken for an error in observations, led to the breakthrough. The team did not expect a complete reversal in direction. Though popular law dictates that there will be a visible effect in energy behavior with the introduction of an observer, the reversal in direction was a surprise.

The reversal in direction can be explained simply as an obstacle restricting flow of energy in a particular direction. If a pipe carrying water is obstructed completely, then the flow is bound to head back in the direction it came from. Similarly, the observer seemed to block the quantum energy, effectively halting and reversing it.

The team hopes that this effect is studied further. Introduction of an observer or the observer effect has shown itself to be a powerful counter force to quantum energy.

According to Rubio, the changes of the current can also be made in a controlled way. Depending on where the observer is inserted, the direction of flow can be changed. The team also found out that certain areas did not produce the extent of direction change as other areas in the system did. All these factors can be used as a mould to guide and manipulate energy on a quantum level, increasing the efficiency of many systems, the team says.

The team hopes that harnessing this property can help with the design of quantum transport devices. Earlier the path was only one-way, but now designs can be more efficient as a single path can facilitate flow in multiple directions. Controlling the heat and current of particles could open up the door to various strategies for directionality modified currents for applications in thermoelectrics, spintronics, phononics and detection, among others.