Scientists led by the University of Massachusetts Amherst have adapted a device called a microwave circulator for use in quantum computers, allowing them for the first time to fine-tune the precise degree of non-reciprocity between a qubit and a qubit, the fundamental unit of quantum computing. microwave. — resonance cavity. The ability to fine-tune the degree of reciprocity is an important tool in quantum information processing.
In doing so, the team, including collaborators from the University of Chicago, derived a general and broadly applicable theory that simplifies and extends older concepts of nonreciprocity; thus, future studies on similar topics may benefit from the team model even when different components are used. and platforms. The study was recently published Science Developments.
Quantum computing is fundamentally different from the bit computing we do every day. A bit is a piece of information usually expressed as 0 or 1. Bits form the basis of all the software, websites and emails that make up our electronic world.
In contrast, quantum computing relies on “quantum bits” or “qubits”, which are similar to ordinary bits except that two states of a quantum object are represented by a “quantum superposition”. Matter in a quantum state behaves very differently, which means that qubits are not just 0 or 1; While it may seem like magic, they can be both at the same time, but they are clearly defined by quantum laws. mechanical. This property of quantum superposition leads to an increase in the energy capabilities of quantum computers.
In addition, a property called “non-reciprocity” could create additional ways for quantum computing to exploit the potential of the quantum world.
“Imagine a conversation between two people,” says Sean van Geldern, a graduate student in physics at UMass Amherst and one of the paper’s authors. “Perfect reciprocity is when each participant in the conversation shares an equal amount of information. Non-reciprocity is when one person shares slightly less than the other.”
“This is a desirable situation in quantum computing,” says senior author Chen Wang, a professor of physics at UMass Amherst, “because there are many computational scenarios where data must be widely accessible without allowing anyone to modify or corrupt the data.”
To check for reciprocity, lead author Ying-Ying Wang, a graduate student in physics at UMass Amherst, and her co-authors ran a series of simulations to determine the design and features their circulators would need to have in order to change their reciprocity. They then built their circulator and conducted a series of experiments to not only prove their concept, but also to fully understand how their device provides reciprocity. By doing this, they were able to revise their model, which contained 16 parameters detailing how to build their device, to a simpler and more general model with only six parameters. This revised, more general model is much more useful than the original, more specific model because it can be broadly applied to many future research endeavors.
The “integrated, non-reciprocal device” created by the team resembles the letter “Y”. At the center of the “Y” is a circulation device that mediates quantum interaction, resembling a circular motion for microwave signals. One of the legs is the resonator port, which is a resonant superconducting cavity that accommodates the electromagnetic field. The other “Y” leg holds the qubit printed on the sapphire chip. The last connection is the output port.
Ying-Ying Wang says: “If we manipulate the superconducting electromagnetic field by bombarding it with photons, we find that this qubit responds in a predictable and controllable way, meaning that we can precisely tune the desired reciprocity. And the simplified model we created allows us to adjust our system to the exact degree of nonreciprocity.” defines it in such a way that external parameters can be calculated for
“This is the first demonstration of imparting invulnerability to a quantum computing device, opening the door to more advanced quantum computing hardware,” says Chen Wang.
Source: Port Altele
