Researchers find new way to control quantum systems

May 4, 2016 by Pamela Smyth, University of Waterloo

Researchers from the Department of Applied Mathematics and the Institute for Quantum Computing at the University of Waterloo have developed a versatile new way of controlling quantum systems that can affect the reliability of experiments.

To develop quantum technologies, it is critical to first build capabilities to control extraordinarily fragile quantum systems. The team from Waterloo found a way to control a quantum system without exposing it to vibration or other interference.

The was published in Physical Review A.

"The idea is to avoid interacting with a quantum system directly," said David Layden, a master's student in the Faculty of Mathematics at Waterloo and lead author of the paper. "Instead, you introduce a second, so-called auxiliary quantum system, such as an atom, for example. You then manipulate it and use it to indirectly affect, and ultimately control, the main system."

Researchers have already used indirect approaches to manipulating quantum systems in several different experiments. But the techniques they used differed based on the particular laboratory setup involved. Each new type of experiment required a different technique.

Now, the Waterloo researchers' one-size-fits-all method of indirectly controlling quantum systems is applicable to any experiment. It involves soft, frequent touches to the main system from the auxiliary one, which allow researchers to freely steer a quantum system while keeping its quantum nature intact.

"These touches are strong enough to fully control the target , but short enough to avoid destroying their quantum properties," said Professor Eduardo Martin-Martinez, of both the Department of Applied Mathematics and Institute for Quantum Computing at Waterloo, and a co-author of this work.

"To achieve this level of control, we must use an auxiliary system that also possesses quantum properties," said Professor Achim Kempf, University Research Chair in the Department of Applied Mathematics at Waterloo, and co-author of the study.

The new technique could play an important role in a number of , which in turn, promise to impact a wide range of fields, from to pharmaceutical drug discovery.

Explore further: Team devises new technique to probe 'noise' in quantum computing

More information: David Layden et al. Universal scheme for indirect quantum control, Physical Review A (2016). DOI: 10.1103/PhysRevA.93.040301

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1 / 5 (2) May 04, 2016
I'm thinking that trying to explain the stabilization of any system will require a more explicit model. QM is designed with limitations, the object follows straightforward physics for charge. Juz say'n How complex is your quantum, i.e a defined probability of a wavelet or a give set of superpositions. Why not define it directly, only so many ways to fit the data. But then you would need to know that all wavelets are produced by specific motion. No magical space-time or hidden negatives within a positive, it's a lot simpler! So exactly what do we control with this method, the event or the probability of the event with less that 100% certainty. Wow all you need is a 3D see thru plate, maybe an abstraction within smart memory, each location is self computing by the neighbors. Or a simple memory correction for changes of objects or change of states. Why try with poor instrumentation. Redefine the memory as smart and the update rate per clock disguised as any scale.
1 / 5 (1) May 04, 2016
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