Quantum ‘Anti-Butterfly Effect’: New Approach to Deal with Complex Computer Performance Developed

A study on the quantum "anti-butterfly effect" has recently solved a longstanding experimental problem in physics and established a method for benchmarking quantum computers' performance.

As specified in a Phys.org report, using the simple, strong protocol the researchers developed, Bin Yan, a quantum theorist at Lost Alamos National Laboratory, explained that they could identify the degree to which quantum computers can efficiently process information, and it applies to information loss in other multifaceted quantum systems, as well.

Yan is the corresponding author of the study on benchmarking information scrambling. Describing their work, he said their protocol measures information scrambling in a quantum system and unambiguously differentiates it from fake positive signals in the noisy background resulting from quantum decoherence.

Coherence and Decoherence

Essentially, noise in decoherence eliminates all the quantum information in a multifaceted system like a quantum computer as it couples with the surrounding environment.

Furthermore, information scrambling through quantum chaos, on the other hand, transmits information throughout the system, shielding it and enabling it for retrieval.

Coherence, in particular, is a quantum state that allows quantum computing. Meanwhile, decoherence refers to losing that state as information leaks to the surrounding environment.

Yan explained that their approach, which is drawing on the quantum anti-butterfly effect they discovered a couple of years back, evolves a system forward and backward through time in one loop, so it can be applied to any system with time-reversing dynamics, which include quantum computers and quantum simulators that use cold atoms.

Simulations on Cloud-Based Computers Shown

The Los Alamos research team showed in their research published in Physical Review Letters that the protocol with simulations on IBM cloud-based quantum computers.

The inability to differentiate decoherence from information scrambling has inhibited an investigational study into the phenomenon. First studied in black-hole physics, information scrambling has proven important throughout many study areas, including quantum chaos in numerous body systems, quantum machine learning, phase transition, and quantum computing.

Moreover, experimental platforms for investigating information scrambling comprise superconductors, trapped ions, and cloud-based quantum computers.

Quantum Anti-Butterfly Effect

Yan and Nikolai Sinitsyn published research in 2020, proving that evolving quantum on a quantum computer backward to damage information in the simulated past is causing a slight change when taken back to the present.

On the contrary, a similar Bioengineer.org report specified that a classical-physics system smears the information "irrecoverably during a back-and-forth time loop."

Building on this discovery, Yan, Sinitsyn, and co-author Joseph Harris, a graduate student at the University of Edinburgh who worked on the present paper as a participant in the Lost Alamos Quantum Computer Summer School, created the protocol.

Such work prepares a quantum system and subsystem. It then evolves the system backward for the same period of time.

Lastly, gauging the overlap of information between a pair of subsystems exhibits how much information has been preserved through scrambling and the amount lost to decoherence.

Related information about quantum computing is shown on Simons Institute's YouTube video below:

Check out more news and information on Quantum Physics in Science Times.