Scientists from Aalto published a paper detailing the results when they used an IBM quantum computer to explore a rarely-studied area of physics by challenging ideas about information around 100 years old at the quantum level. The paper is titled ‘Quantum simulation of parity–time symmetry breaking with a superconducting quantum processor’.

Quantum physics requires the use of mathematical operators called Hermitian Hamiltonians. They have been used for almost 100 years, but some theorists have recently found out that they could use Hermitian operators with equations that are not Hermitian. These new equations would describe a universe with its own rules. For example, looking in the mirror and reversing time’s direction will still let you see the same version of yourself as in the real world.

In a new paper, Docent Sorin Paraoanu and his team used a quantum computer to construct such a universe. His team includes Dr. Shruti Dogra from Aalto University, who is the paper’s first author, as well as Artem Melnikov from MIPT and Terra Quantum.

The quantum computer’s qubits were modified to use the new rules. The scientists then experimented with the universe to produce some results forbidden by normal Hermitian quantum mechanics. Firstly, applying operations to the qubits did not conserve quantum information. This is a standard behaviour that has caused even Stephen Hawking to fail at solving problems such as his black hole information paradox.

The second result was when they experimented with entangled qubits. This is when two qubits are made to connect to each other in some way. Einstein was uncomfortable with entanglement and called it ‘spooky action at a distance’. In normal quantum physics, the degree of entanglement between two particles is not alterable, but the new rules proved that the scientists could do so.

There are some potential applications of this research. Some novel optical or microwave-based devices follow similar rules. The study’s information can prove crucial in simulating these devices on quantum computers.