Quantum Time Flip

It’s been 35 years since Cher first wanted to turn back time, but it turns out that quantum mechanics might have allowed for this wild reversal all along. In new research, scientists from China and Hong Kong show that—in certain quantum systems—the time variable can be reversed by creating a double superposition (one each in opposite directions) and still bear out valid results. 

What results from this little bit of quantum trickery is both an input and output that are considered indefinite, meaning that either one can be the input or the output. Basically, the after can go before the before. The peer-reviewed research appears in the journal Physical Review Letters.

In our day-to-day lives, we perceive time as marching inexorably forward, and that means many processes aren’t easily reversible. You can’t put the toothpaste back in the tube, so to speak—it’s a lot more difficult to reset an object back to its original state than it is to change it in the first place. This is called time’s arrow, and we believe it’s partly caused by the fact that our universe has been ever-expanding since the Big Bang.     READ MORE...

Decoding Quantum Nonlocality

Entangled quantum objects can be used to network separated systems. The researchers demonstrate what is needed for nonlocal correlations, a requirement for a useful quantum

network. Credit: The Grainger College of Engineering at the University of Illinois Urbana-Champaign/Wesley Moore

Researchers have developed a theoretical framework that provides deeper insights into quantum nonlocality, a vital property for quantum networks to outperform classical technology. Their study unified previous nonlocality research and showed that nonlocality is achievable only through a restricted set of quantum operations. This framework could aid in evaluating the quality of quantum networks and broaden our understanding of nonlocality.

Introduction and Overview
A new theoretical study has been conducted, providing a framework for understanding nonlocality. This is a crucial characteristic that quantum networks must exhibit to perform tasks unachievable by traditional communications technology. The researchers involved clarified the concept of nonlocality, outlining the conditions necessary for establishing systems with potent quantum correlations.

Nonlocality and Quantum Computing
Published in the journal Physical Review Letters, the study adapted techniques from quantum computing theory to form a novel classification scheme for quantum nonlocality. This adaptation not only enabled researchers to merge previous studies of the concept into a single framework, but also allowed them to prove that networked quantum systems can only exhibit nonlocality if they possess a specific set of quantum features.


Eric Chitambar, a professor of electrical and computer engineering at the University of Illinois Urbana-Champaign and the project lead, explained, “On the surface, quantum computing and nonlocality in quantum networks are different things, but our study shows that, in certain ways, they are two sides of the same coin. In particular, they require the same fundamental set of quantum operations to deliver effects that cannot be replicated with classical technology.”  READ MORE...