New work from IBM highlights potential quantum speedups for differential equations
Category: quantum physics – Page 2
2D discrete time crystals realized on a quantum computer for the first time
Physical systems become inherently more complicated and difficult to produce in a lab as the number of dimensions they exist in increases—even more so in quantum systems. While discrete time crystals (DTCs) had been previously demonstrated in one dimension, two-dimensional DTCs were known to exist only theoretically. But now, a new study, published in Nature Communications, has demonstrated the existence of a DTC in a two-dimensional system using a 144-qubit quantum processor.
Like regular crystalline materials, DTCs exhibit a kind of periodicity. However, the crystalline materials most people are familiar with have a periodically repeating structure in space, while the particles in DTCs exhibit periodic motion over time. They represent a phase of matter that breaks time-translation symmetry under a periodic driving force and cannot experience an equilibrium state.
“Consequently, local observables exhibit oscillations with a period that is a multiple of the driving frequency, persisting indefinitely in perfectly isolated systems. This subharmonic response represents a spontaneous breaking of discrete time-translation symmetry, analogous to the breaking of continuous spatial symmetry in conventional solid-state crystals,” the authors of the new study explain.
Stephen Wolfram: computation is the universe’s OS
Mathematica creator Stephen Wolfram has spent nearly 50 years arguing that simple computational rules underlie everything from animal patterns to the laws of physics. In his 2023 TED talk, he makes the case that computation isn’t just a useful way to model the world — it’s the fundamental operating system of reality itself.
Wolfram introduces “the ruliad,” an abstract concept encompassing all possible computational processes. Space and matter, he argues, consist of discrete elements governed by simple rules. Gravity and quantum mechanics emerge from the same computational framework. The laws of physics themselves are observer-dependent, arising from our limited perspective within an infinite computational structure.
On AI, Wolfram sees large language models as demonstrating deep connections between semantic grammar and computational thinking. The Wolfram Language, he claims, bridges human conceptualization and computational power, letting people operationalize ideas directly — what he calls a “superpower” for thinking and creation.
Measuring the quantum extent of a single molecule confined to a nanodroplet
There is no measurement that can directly observe the wave function of a quantum mechanical system, but the wave function is still enormously useful as its (complex) square represents the probability density of the system or elements of the system. But for a confined system, the wave function can be inferred.
Scientists from China have now shown that the wave function’s dependence in space can be determined for a single molecule embedded in a superfluid helium nanodroplet. Their research has been published in the journal Physical Review Letters.
A New Ingredient for Quantum Error Correction
Entanglement and so-called magic states have long been viewed as the key resources for quantum error correction. Now contextuality, a hallmark of quantum theory, joins them as a complementary resource.
Machines make mistakes, and as they scale up, so too do the opportunities for error. Quantum computers are no exception; in fact, their errors are especially frequent and difficult to control. This fragility has long been a central obstacle to building large-scale devices capable of practical, universal quantum computation. Quantum error correction attempts to circumvent this obstacle, not by eliminating sources of error but by encoding quantum information in such a way that errors can be detected and corrected as they occur [1]. In doing so, the approach enables fault-tolerant quantum computation. Over the past few decades, researchers have learned that this robustness relies on intrinsically quantum resources, most notably, entanglement [2] and, more recently, so-called magic states [3].
Superfluids are supposed to flow indefinitely. Physicists just watched one stop moving
Ordinary matter, when cooled, transitions from a gas into a liquid. Cool it further still, and it freezes into a solid. Quantum matter, however, can behave very differently. In the early 20th century, researchers discovered that when helium is cooled, it transitions from a seemingly ordinary gas into a so-called superfluid. Superfluids flow without losing any energy, among other quantum quirks, like an ability to climb out of containers.
What happens when you cool a superfluid down even more? The answer to this question has eluded physicists since they first started asking it half a century ago.
Quantum batteries could quadruple qubit capacity while reducing energy infrastructure requirements
Scientists have unveiled a new approach to powering quantum computers using quantum batteries—a breakthrough that could make future computers faster, more reliable, and more energy efficient.
Quantum computers rely on the rules of quantum physics to solve problems that could transform computing, medicine, energy, finance, communications, and many other fields in the years ahead.
But sustaining their delicate quantum states typically requires room-sized, energy-intensive cryogenic cooling systems, as well as a system of room-temperature electronics.
New light-based platform sets the stage for future quantum supercomputers
A light has emerged at the end of the tunnel in the long pursuit of developing quantum computers, which are expected to radically reduce the time needed to perform some complex calculations from thousands of years down to a matter of hours.
A team led by Stanford physicists has developed a new type of “optical cavity” that can efficiently collect single photons, the fundamental particle of light, from single atoms. These atoms act as the building blocks of a quantum computer by storing “qubits”—the quantum version of a normal computer’s bits of zeros and ones. This work enables that process for all qubits simultaneously, for the first time.
In a study published in Nature, the researchers describe an array of 40 cavities containing 40 individual atom qubits as well as a prototype with more than 500 cavities. The findings indicate a way to ultimately create a million-qubit quantum computer network.