Researchers have discovered that hidden symmetry can be the key to stronger quantum systems.

Researchers have found a way to protect ultra-fragile quantum systems from noise, which could help in the design and development of new quantum devices such as ultra-powerful quantum computers.

Researchers at the University of Cambridge have shown that microbial particles can remain internally attached or trapped for long distances, even if random interruptions occur between them. Using the mathematics of quantum theory, they found a simple setup where trapped particles could be prepared and stabilized even in the presence of sound, taking advantage of previously unknown symmetry in a quantum system.

Their results, reported in the journal Physical Review Letters, Open a new window into the mysterious quantum world that could revolutionize future technology by preserving quantum effects in noisy environments, the biggest obstacle to the development of such technology. Enhancing this capability will be at the heart of ultrafast quantum computers.

Quantum systems are built on the bizarre behavior of particles at the atomic level and can revolutionize the way complex calculations are performed. While a typical computer beat is an electrical switch that can be set to one or zero, a quantum bit or qubit can be set to one, zero, or both at the same time. Moreover, when two quibs are trapped, the operation on one immediately affects the other, no matter how far away it is. This dual state is what gives the quantum computer its power. A computer made up of entangled quits instead of ordinary bits can perform calculations well beyond the capabilities of the most powerful supercomputers.

“Nevertheless, quibits are very beautiful things and the smallest sound in their environment can be broken in their wrap,” said Dr. Shovan Dutta said. “Their real-world applications will be limited until we find a way to make quantum systems stronger.”

Some companies, in particular, IBM and Google have developed working quantum computers, although so far they are limited to less than 100 qubits. They require almost isolation from sound, and even then, some microseconds have a very short lifespan. Both companies plan to develop 1000 quintal quantum computers in the next few years, although quantum computers will not reach practical use until stability issues are addressed.

Now, Dutta and his co-author Professor Nigel Cooper have found a robust quantum system where a pair of quibits are trapped despite a lot of noise.

They model the atomic system in lattice formation, where atoms move from one site of the lattice to another, interacting strongly with each other. The authors found that if sound is added between the lattice, it does not affect the particles trapped between the left and right sides. This surprising feature results from a special kind of symmetry that protects the number of such entangled pairs.

“We didn’t expect this kind of static kind of trap,” Dutta said. “We stumbled upon this hidden symmetry, which is very rare in these noisy systems.”

They showed that this hidden symmetry protects the spread pairs and allows their number to be controlled from zero to a large maximum value. Similar conclusions can be applied to a wide class of physical systems and can be realized with components that already exist in experimental platforms, paving the way for control in noisy environments.

“Uncontrolled environmental disturbances are as bad for the existence of quantum effects as dispersion, but one can learn a lot by deliberately engineering certain types of disturbances and seeing how particles react,” Dutta said. “We have shown that a simple type of disruption can actually create and save a lot of entangled pairs, which is a great impetus for the experimental development of this field.”

Researchers hope to confirm their theoretical findings through experiments in the coming year.

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