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Category: quantum physics – Page 10

Physicist proves unsolvability beyond one dimension for quantum Ising models

By extending a proof of a physically important behavior in one-dimensional quantum spin systems to higher dimensions, a RIKEN physicist has shown in a new study that the model lacks exact solutions. The research is published in the journal Physical Review B.

Theoretical physicists develop mathematical models to describe material systems, which they can then use to make predictions about how materials will behave.

One of the most important models is the Ising model, which was first developed about a century ago to model such as iron and nickel.

Physicists create new electrically controlled silicon-based quantum device

A team of scientists at Simon Fraser University’s Quantum Technology Lab and leading Canada-based quantum company Photonic Inc. have created a new type of silicon-based quantum device controlled both optically and electrically, marking the latest breakthrough in the global quantum computing race.

The research, published in the journal Nature Photonics, reveals new diode nanocavity devices for electrical control over silicon color center qubits.

The devices have achieved the first-ever demonstration of an electrically-injected single-photon source in silicon. The breakthrough clears another hurdle toward building a quantum computer—which has enormous potential to provide computing power well beyond that of today’s supercomputers and advance fields like chemistry, materials science, medicine and cybersecurity.

Advanced AI links atomic structure to quantum tech

A research team led by Oak Ridge National Laboratory has developed a new method to uncover the atomic origins of unusual material behavior. This approach uses Bayesian deep learning, a form of artificial intelligence that combines probability theory and neural networks to analyze complex datasets with exceptional efficiency.

The technique reduces the amount of time needed for experiments. It helps researchers explore sample regions widely and rapidly converge on important features that exhibit interesting properties.

“This method makes it possible to study a material’s properties with much greater efficiency,” said ORNL’s Ganesh Narasimha. “Usually, we would need to scan a large region, and then several small regions, and perform spectroscopy, which is very time-consuming. Here, the AI algorithm takes control and does this process automatically and intelligently.”

Universal scheme efficiently generates arbitrary two-qubit gates in superconducting quantum processors

The operation of quantum computers, systems that process information leveraging quantum mechanical effects, relies on the implementation of quantum logic gates. These are essentially operations that manipulate qubits, units of information that can exist in a superposition of states and can become entangled.

A type of quantum logic gate that enables the entanglement between is a so-called two-qubit gate. Notably, most existing schemes for generating these gates force qubits outside of the conditions or parameters in which they can best store information and are easier to control.

Researchers at the Beijing Academy of Quantum Information Sciences (BAQIS) and Tsinghua University recently introduced a new universal scheme to implement two-qubit gates in superconducting quantum processors. This scheme, outlined in a paper published in Nature Physics, was found to reliably enable the generation of entanglement between qubits in superconductor-based quantum computers.

If quantum computing is answering unknowable questions, how do we know they’re right?

Quantum computing promises to solve the seemingly unsolvable in fields such as physics, medicine, cryptography and more.

But as the race to develop the first large-scale, error-free commercial device heats up, it begs the question: how can we check that these ‘impossible’ solutions are correct?

A new Swinburne study is tackling this paradox. The paper is published in the journal Quantum Science and Technology.

World-first quantum computer made with standard laptop chips launched

A UK startup has made a revolutionary advancement after delivering the world’s first full-stack quantum computer, built using the same silicon chip technology found in smartphones and laptops.

London-based Quantum Motion, a quantum computing startup that develops scalable quantum computing tech using silicon, launched the industry’s first full-stack quantum computer made with silicon. It was deployed at the UK National Quantum Computing Centre (NQCC).

Single device amplifies signals while shielding qubits from unwanted noise

Quantum computing, an approach to deriving information that leverages quantum mechanical effects, relies on qubits, quantum units of information that can exist in superpositions of states. To effectively perform quantum computing, engineers and physicists need to be able to measure the state of qubits efficiently.

In quantum computers based on , qubits are indirectly measured by a so-called readout resonator, a circuit that responds differently based on the state of a . This circuit’s responses are probed using a weak electromagnetic wave, which needs to be amplified to enable its detection.

To amplify these signals, also known as microwave tones, quantum technology engineers rely on devices known as amplifiers. Existing amplifiers, however, have notable limitations. Conventional amplifiers can send unwanted noise back to the qubit, disturbing its state. Superconducting parametric amplifiers introduced more recently can be very efficient, but they conventionally rely on bulky and magnetic hardware components that control the direction of signal and protect qubits from backaction noise.

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