Quantum computers are powerful computing devices that rely on quantum mechanics, or the science of how particles like electrons and atoms interact with the world around them. These devices could potentially be used to solve certain types of computational problems in a much shorter time.
Scientists have long hoped that quantum computing could be the next big computing breakthrough; however, existing limitations prevented the technology from reaching its true potential. For these computers to work, the basic unit of information integral to their operation, known as quantum bits or qubits, must be stable and fast.
Qubits are represented both by simple binary quantum states and by various physical implementations. A promising candidate is a trapped electron that levitates in a vacuum. However, controlling the quantum states, especially the vibrational motions, of trapped electrons can be difficult.
In an article published in Physical examination research, researchers have identified possible solutions to some of the limitations of qubits for quantum computing. They examined two different hybrid quantum systems: an electron-superconductor circuit and a coupled electron-ion system. Both systems were able to control the temperature and the movement of the electron.
“We have found a way to cool and measure the motion of a levitating electron in a vacuum, or a trapped electron, both in the quantum regime,” said Assistant Professor Alto Osada at the Komaba Institute for Science. from the University of Tokyo. “With the feasibility of quantum-level control of the motion of trapped electrons, the trapped electron becomes more promising and attractive for quantum technology applications, such as quantum computing.”
The proposed systems the researchers focused on included an electron trapped in a vacuum called a Paul trap interacting with superconducting circuits and a trapped ion. Because ions are positively charged and electrons are negatively charged, when they are trapped together they move towards each other due to a phenomenon called Coulomb attraction.
Because the electron has such a light mass, the interactions between the electron and the circuit and the electron and the ion were particularly strong. They also discovered that they were able to control the temperature of the electron using microwave fields and optical lasers.
Another important metric the researchers used to measure the success of their calculations was the phonon mode of the electron. Phonon refers to a unit of energy that characterizes a vibration or, in this case, the oscillation of the trapped electron. The desirable result was single-phonon readout and ground-state cooling. Ground state cooling refers to the frozen state of the electron.
The researchers were able to accomplish them thanks to their two hybrid systems which they analyzed. “Highly efficient and high-fidelity quantum operations are available in the trapped electron system,” Osada said. “This new system manifests as a new playground for the development of quantum technologies.”
Looking ahead, the researchers note that further experimental research will need to be conducted to see if their methods can be implemented and applied to quantum computing. For example, they plan to demonstrate their idea with a proof-of-concept experiment. “We plan to examine our schemes using electrons trapped in a microwave cavity,” Osada said. “Thanks to this research, we will be able to take a step closer to precise quantum operations and to the implementation of quantum computing.”
A multi-qubit molecular model system for quantum computing
Alto Osada et al, Feasibility study on ground-state cooling and single-phonon readout of trapped electrons using hybrid quantum systems, Physical examination research (2022). DOI: 10.1103/PhysRevResearch.4.033245
Provided by University of Tokyo
Quote: Reading out a single phonon and cooling the ground state with a trapped electron brings quantum computing closer (2022, October 21) Retrieved on October 21, 2022 from https://phys.org/news/2022-10 -single-phonon-readout-solar-state-cooling-electron.html
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