Aalto researchers have used an IBM quantum computer to explore an overlooked area of physics, and have challenged 100-year-old notions about information at the quantum level.

The rules of quantum physics, which govern how very small things behave, use mathematical operators called Hermitian Hamiltonians. Hermitian operators have underpinned quantum physics for nearly 100 years, but recently, theorists have realized that it is possible to extend its fundamental equations to the use of Hermitian operators that are not Hermitian. The new equations describe a universe with its own peculiar set of rules: For example, by looking in the mirror and reversing the direction of time, you should see the same version of you as in the actual world. In their new paper, a team of researchers led by Docent Sorin Paraoanu used a quantum computer to create a toy universe that behaves according to these new rules. The team includes Dr. Shruti Dogra from Aalto University, first author of the paper, and Artem Melnikov, from MIPT and Terra Quantum.

The researchers made qubits, the part of the quantum computer that carries out calculations, behave according to the new rules of non-Hermitian quantum mechanics. They demonstrated experimentally a couple of exciting results that are forbidden by regular Hermitian quantum mechanics. The first discovery was that applying operations to the qubits did not conserve quantum information—a behavior so fundamental to standard quantum theory that it results in currently unsolved problems like Stephen Hawking's black hole information paradox. The second exciting result came when they experimented with two entangled qubits.

Entanglement is a type of correlation that appears between qubits, as if they have a magic connection that makes them behave in sync with each other. Einstein was famously uncomfortable with this concept, referring to it as "spooky action at a distance." Under regular quantum physics, it is not possible to alter the degree of entanglement between two particles by tampering with one of the particles on its own. However, in non-Hermitian quantum mechanics, the researchers were able to alter the level of entanglement of the qubits by manipulating just one of them, a result that is expressly off-limits in regular quantum physics.

"The exciting thing about these results is that quantum computers are now developed enough to start using them for testing unconventional ideas that have been only mathematical so far," said Sorin Paraoanu. "With the present work, Einstein's 'spooky action at a distance' becomes even spookier. And although we understand very well what is going on, it still gives you the shivers."

The research also has potential applications. Several novel optical or microwave-based devices developed in recent times do seem to behave according to the new rules. The present work opens the way to simulating these devices on quantum computers.

The paper, "Quantum simulation of parity-time symmetry breaking with a superconducting quantum processor," is published in *Communications Physics*.

lmjRPinfyuNBOWo

Everything is very open with a clear explanation of the challenges.

It was truly informative.

Your website is very useful.

Thanks for sharing!

Many thanks for sharing. I more than happy for the info

I check out from you.

excellent and amazing blog. I truly wish to thanks,

for providing us far better info.

excellent as well as incredible blog site. I really want to thank you, for providing us much better details.

I have actually checked out a few of the articles on your blog currently, and I actually like your posting style.

I do not know whether It’s just me or if perhaps everybody else

experiencing problems with your site.

It appears as though some of the

written text in your content are running off

the screen. Can someone else please provide feedback and let me

know if this is happening to them as well?

This might be a issue with my

web browser because I’ve had this happen previously.

Cheers

I haven’t had time to update the CSS but I’ll take care of the text off screen right now. Thanks for the info.

Well, Rochelle, I’ve checked it out from 300px up to 1200px and it seems to be scaling alright for me. If you get a chance, please let me know what device and browser you’re using so I can reproduce this. Thanks!