A key experimental device for future quantum physics-based technologies that borrows a page from current, everyday mechanical devices has been developed by researchers.
Reliable, compact, durable, and efficient acoustic devices harness mechanical motion to perform useful tasks. The mechanical oscillator is a prime example. components of the device begin moving back-and-forth about their original position when displaced by a sound. Creating periodic motion is a way to keep time, signal, and sense in electronics, including phones, computers, and watches.
The benefits of mechanical systems have been sought to bring into the quantum realm, where atoms delicately interact and behave in counterintuitive ways. A group of researchers led by Amir Safavi-Naeini of the University of California, Berkeley, have demonstrated new capabilities by attaching tiny mechanical oscillators with a type of circuit that can store and process energy in the form of a qubit. The researchers can manipulate the quantum state of mechanical oscillators using the device's qubit.
The device has shown an important next step in trying to build quantum computers and other useful quantum devices based on mechanical systems. The new study was published in the journal Nature.
There are quantum effects on computer chips.
The first authors of the study were Alex and Agnetta. The researchers wore white bunny suits while working in the cleanrooms on the campus in order to prevent the spread of harmful particles.
Hardware components were fabricated at nanometer-scale resolutions onto two computer chips. The researchers stuck the two chips together so the components on the bottom chip faced the ones on the top.
The aluminum circuit that forms the qubit was created by the two men. Sending microwaves into this circuit creates light particles that are used to store information in the device. Weighted combinations of 0 and 1 can be represented by qubits in quantum mechanical devices, which store bits as voltages. This is because of the quantum mechanical phenomenon known as superposition, where a quantum system exists in multiple quantum states at once until the system is measured.
The way reality works at the quantum mechanical level is very different from our experience of the world.
The top chip has two small, bridge-like crystal structures that are just a few tens of nanometers long. The material used to make the crystals is niobate. The electric field conveyed by the qubit photon can be converted into a single unit of energy called a phonon by using materials with this property.
Sound waves are quantized into particles called phonons, and by combining energy of these different forms in our device, we create a hybrid.
The smallest possible data-holding element in a computer, and with the qubit supplying the data, was allowed by the generation of these phonons. Like the qubit, the oscillators can be excited and not excited at the same time. The researchers were able to prepare, read out, and modify the data stored in the register with the help of the superconducting circuit.
The dream is to make a device that works the same way as a computer chip, for example, in your phone or thumb drive.
Enhancing entanglement.
Beyond superposition, there is a connection between the photons and the resonators in the device. It's notoriously difficult to create entangled states in the lab because the information about the state of the system is distributed across a number of components. It is possible to know everything about two particles together, but nothing about one of them. Imagine two coins that are flipped in two different places, and that are observed to land as heads or tails randomly with equal probability, but when measurements at the different places are compared, they are always correlated; that is, if one coin lands as tails, the other coin is guaranteed to land
The manipulation of multiple qubits, all in superposition and entangled, is the key to quantum computing.
To demonstrate the quantum effects in the experiment, a single qubit was stored as a photon in the circuit on the bottom chip. After exchanging energy with one of the mechanical oscillators on the top chip, the remaining information was transferred to the second mechanical device. The researchers used the circuit as a tool to quantum mechanically entangle the two mechanical resonators with each other.
The strangeness of quantum mechanics is on full display here.
The period of sustained coherence would need to be on the order of seconds instead of fractions of seconds. Superposition and entangle are both very delicate conditions, vulnerable to even slight changes in the form of heat or other energy. Longer coherence times can be achieved by honing fabrication processes and improving materials.
Over the last four years, we have improved the performance of our system by nearly 10 times every year.
More information: E. Alex Wollack et al, Quantum state preparation and tomography of entangled mechanical resonators, Nature (2022). DOI: 10.1038/s41586-022-04500-y Journal information: Nature Citation: New hardware integrates mechanical devices into quantum tech (2022, April 22) retrieved 22 April 2022 from https://phys.org/news/2022-04-hardware-mechanical-devices-quantum-tech.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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