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Category: quantum physics – Page 5

A new high-performance quantum processor boasts 105 superconducting qubits and rivals Google’s acclaimed Willow processor.

In the quest for useful quantum computers, processors based on superconducting qubits are especially promising. These devices are both programmable and capable of error correction. In December 2024, researchers at Google Quantum AI in California reported a 105-qubit superconducting processor known as Willow (see Research News: Cracking the Challenge of Quantum Error Correction) [1]. Now Jian-Wei Pan at the University of Science and Technology of China and colleagues have demonstrated their own 105-qubit processor, Zuchongzhi 3.0 (Fig. 1) [2]. The two processors have similar performances, indicating a neck-and-neck race between the two groups.

Quantum advantage is the claim that a quantum computer can perform a specific task faster than the most powerful nonquantum, or classical, computer. A standard task for this purpose is called random circuit sampling, and it works as follows. The quantum computer applies a sequence of randomly ordered operations, known as a random circuit, to a set of qubits. This circuit transforms the qubits in a unique and complex way. The computer then measures the final states of the qubits. By repeating this process many times with different random circuits, the quantum computer records a probability distribution of final qubit states.

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For decades, scientists have relied on electrodes and dyes to track the electrical activity of living cells. Now, engineers at the University of California San Diego have discovered that quantum materials just a single atom thick can do the job—using only light.

A new study, published in Nature Photonics, shows that these ultra-thin semiconductors, which trap electrons in two dimensions, can be used to sense the biological electrical activity of living cells with high speed and resolution.

Scientists have continually been seeking better ways to track the electrical activity of the body’s most excitable cells, such as neurons, heart muscle fibers and pancreatic cells. These tiny electrical pulses orchestrate everything from thought to movement to metabolism, but capturing them in real time and at large scales has remained a challenge.

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Light was long considered to be a wave, exhibiting the phenomenon of interference in which ripples like those in water waves are generated under specific interactions. Light also bends around corners, resulting in fringing effects, which is termed diffraction. The energy of light is associated with its intensity and is proportional to the square of the amplitude of the electric field, but in the photoelectric effect, the energy of emitted electrons is found to be proportional to the frequency of radiation.

This observation was first made by Philipp Lenard, who did initial work on the photoelectric effect. In order to explain this, in 1905, Einstein suggested in Annalen der Physik that light comprises quantized packets of , which came to be called photons. It led to the theory of the dual nature of light, according to which light can behave like a wave or a particle depending on its interactions, paving the way for the birth of quantum mechanics.

Although Einstein’s work on photons found broader acceptance, eventually leading to his Nobel Prize in Physics, Einstein was not fully convinced. He wrote in a 1951 letter, “All the 50 years of conscious brooding have brought me no closer to the answer to the question: What are light quanta?”

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From computer chips to image sensors in cameras, today’s technology is overwhelmingly based on a semiconductor called silicon. This technology has been shrinking for decades—think of early room-sized computers compared to today’s desktops—but physical limitations will soon prevent further improvement.

That’s why scientists and engineers are preparing for a new generation of technology—one based on quantum mechanics.

The electrons in so-called “” behave differently than those in silicon, enabling more complex behaviors, like magnetism and superconductivity, that are useful for future quantum technologies.

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Vanishing atoms can ruin quantum calculations. Scientists have a new plan to locate leaks.

Quantum computers face a major challenge: atoms, which serve as their qubits, can vanish without warning, corrupting calculations. Researchers have developed a groundbreaking method to detect this problem in neutral-atom quantum systems without disrupting their state. This discovery helps overcome a key hurdle in making quantum computing.

Performing computation using quantum-mechanical phenomena such as superposition and entanglement.

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Using lattice quantum chromodynamics, researchers have created what is likely the smallest force field map ever generated. Their findings reveal astonishingly powerful interactions, akin to the weight of 10 elephants squeezed into a space smaller than an atomic nucleus.

Mapping the Forces Inside a Proton

Scientists have successfully mapped the forces inside a proton, revealing in unprecedented detail how quarks—the tiny particles within—react when struck by high-energy photons.

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Phase transitions are a familiar part of life, representing predictable paths by which solids turn to liquids, mixtures turn to solutions, magnets become nonmagnetic. Temperature plays a central role in driving many phase transitions, however there are others that don’t depend on temperature at all—such as instabilities in social networks, bird flocking, and even the process of visual recognition in humans. Phase transitions represent change that impacts all length scales from the tiniest to the global, becoming permanent on time scales from the shortest to the longest. Most enigmatic are phase transitions that happen only at zero temperature, driven by the intrinsic quantum mechanical nature of matter. How are these quantum phase transitions different from temperature driven phase transitions? What are the different phases that can be explored by quantum systems at zero temperature? Living as we do at nonzero temperature, can we experience quantum phenomena that occur at zero temperature? Phase transitions and the ways in which they pattern space and time are at the heart of our developing understanding of quantum matter.

Meigan Aronson is an experimental condensed matter physicist whose research centers on the discovery and exploration of quantum materials. She received her undergraduate degree from Bryn Mawr College, and her PhD in Physics from the University of Illinois at Urbana-Champaign. After a postdoc at Los Alamos National Laboratory, she enjoyed faculty positions at the University of Michigan and at Stony Brook University, where she was also a group leader at Brookhaven National Laboratory. Her research uses neutron scattering to study the emergence of new phases of matter, especially novel types of order that are only found near quantum phase transitions. She is a Fellow of the American Physical Society and the Neutron Scattering Society of America, and has received the Department of Defense National Security Science and Engineering Fellowship. She is currently a Professor in the Department of Physics and Astronomy and a Principal Investigator at the Stewart Blusson Quantum Matter Institute at The University of British Columbia, where she also served as Dean of the Faculty of Science.

This public lecture was recorded at Aspen Center for Physics on Wednesday, February 26, 2025. Thank you to the Nick and Maggie DeWolf Foundation for making our winter lecture series possible since 1985.

#quantumphasetransitions #spin #quantummechanics #neutronscattering #quantumphases #physics

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Zuchongzhi-3, a superconducting quantum computing prototype with 105 qubits and 182 couplers, has made significant advancements in random quantum circuit sampling. This prototype was successfully developed by a research team from the University of Science and Technology of China (USTC).

This prototype operates at a speed that is 1015 times faster than the currently available and one million times faster than the latest results published by Google. This achievement marks a milestone in enhancing the performance of quantum computation, following the success of Zuchongzhi-2. The research findings have been published as the cover article in Physical Review Letters.

Quantum supremacy is the demonstration of a quantum computer capable of performing tasks that are infeasible for classical computers. In 2019, Google’s 53-qubit Sycamore processor completed a random circuit sampling task in 200 seconds, a task that would have taken approximately 10,000 years to simulate on the world’s fastest supercomputer at the time.

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