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Category: quantum physics

Ringing black hole confirms Einstein and Hawking’s predictions

A decade ago, scientists first detected ripples in the fabric of space-time, called gravitational waves, from the collision of two black holes. Now, thanks to improved technology and a bit of luck, a newly detected black hole merger is providing the clearest evidence yet of how black holes work—and, in the process, offering long-sought confirmation of fundamental predictions by Albert Einstein and Stephen Hawking.

The new measurements were made by the Laser Interferometer Gravitational-Wave Observatory (LIGO), with analyses led by astrophysicists Maximiliano Isi and Will Farr of the Flatiron Institute’s Center for Computational Astrophysics in New York City. The results reveal insights into the properties of black holes and the fundamental nature of space-time, hinting at how quantum physics and Einstein’s general relativity fit together.

“This is the clearest view yet of the nature of black holes,” says Isi, who is also an assistant professor at Columbia University. “We’ve found some of the strongest evidence yet that astrophysical black holes are the black holes predicted from Albert Einstein’s theory of general relativity.”

In quantum sensing, what beats beating noise? Meeting noise halfway

Noise is annoying, whether you’re trying to sleep or exploit the laws of quantum physics. Although noise from environmental disturbances will always be with us, a team including scientists at the National Institute of Standards and Technology (NIST) may have found a new way of dealing with it at the microscopic scales where quantum physics reigns. Addressing this noise could make possible the best sensors ever made, with applications ranging from health care to mineral exploration.

By taking advantage of quantum phenomena known as superposition and entanglement, researchers can measure subtle changes in the environment useful for everything from geology to GPS. But to do this, they must be able to see through the caused by environmental sources such as stray magnetic fields to detect, for example, an important signal from the brain.

New findings, detailed today in Physical Review Letters, would enable interlinked groups of quantum objects such as atoms to better sense the environment in the presence of noise. A horde of unlinked quantum objects can already outperform a conventional sensor. Linking them through the process of quantum entanglement can make them perform better still. However, entangling the group can make it vulnerable to environmental noise that causes errors, making the group lose its additional sensing advantage.

Advanced X-ray technique enables first direct observation of magnon spin currents

Spintronics is an emerging field that leverages the spin, or the intrinsic angular momentum, of electrons. By harnessing this quantum-relativistic property, researchers aim to develop devices that store and transmit information faster, more efficiently, and at higher data densities, potentially making devices much smaller than what is possible today. These advances could drive next-generation memory, sensors, and even quantum technologies.

A key step toward this future is the control of “spin currents,” the flow of angular momentum through a material without an accompanying electrical charge current. However, spin currents have proven notoriously difficult to measure directly—until now.

In a new study, a research team led by scientists at the National Synchrotron Light Source II (NSLS-II)—a U.S. Department of Energy (DOE) Office of Science user facility at DOE’s Brookhaven National Laboratory—used a technique called resonant inelastic X-ray scattering (RIXS) to detect a current formed by the flow of magnons, quantized spin-wave excitations in a material’s magnetic structure.

Exotic phase of matter realized on quantum processor

Phases of matter are the basic states that matter can take—like water that can occur in a liquid or ice phase. Traditionally, these phases are defined under equilibrium conditions, where the system is stable over time. But nature allows for stranger possibilities: new phases that emerge only when a system is driven out of equilibrium. In a new study published in Nature, a research team shows that quantum computers offer an unparalleled way to explore those exotic states of matter.

Unlike conventional phases of , the so-called nonequilibrium quantum phases are defined by their dynamical and time-evolving properties—a behavior that cannot be captured by traditional equilibrium thermodynamics.

One particularly rich class of nonequilibrium states arises in Floquet systems— that are periodically driven in time. This rhythmic driving can give rise to entirely new forms of order that cannot exist under any equilibrium conditions, revealing phenomena that are fundamentally beyond the reach of conventional phases of matter.

Measuring electron pulses for future compact ultra-bright X-ray sources

In a step toward making ultra-bright X-ray sources more widely available, an international collaboration led by the University of Michigan—with experiments at the U.K.’s Central Laser Facility—has mapped key aspects of electron pulses that can go on to generate laser-like X-ray pulses.

These X-ray pulses have the potential to advance chemistry, biology, and physics by enabling researchers to measure the way molecules behave in great detail. The technique may also be useful in clinical medicine for imaging soft tissues and organs.

Because the pulses are so short, quadrillionths of a second (femtoseconds) long, they can take snapshots of chemical reactions, revealing the choreography of atoms and molecules, including larger biomolecules such as proteins. These studies are valuable for both basic research, down to quantum mechanics, and applications of chemistry such as drug discovery.

What Is Superposition and Why Is It Important?

Imagine touching the surface of a pond at two different points at the same time. Waves would spread outward from each point, eventually overlapping to form a more complex pattern. This is a superposition of waves. Similarly, in quantum science, objects such as electrons and photons have wavelike properties that can combine and become what is called superposed.

While waves on the surface of a pond are formed by the movement of water, quantum waves are mathematical. They are expressed as equations that describe the probabilities of an object existing in a given state or having a particular property. The equations might provide information on the probability of an electron moving at a specific speed or residing in a certain location. When an electron is in superposition, its different states can be thought of as separate outcomes, each with a particular probability of being observed. An electron might be said to be in a superposition of two different velocities or in two places at once. Understanding superposition may help to advance quantum technology such as quantum computers.

One of the fundamental principles of quantum mechanics, superposition explains how a quantum state can be represented as the sum of two or more states.

Scientists Turned Our Cells Into Quantum Computers—Sort Of

For the protein qubit to “encode” more information about what is going on inside a cell, the fluorescent protein needs to be genetically engineered to match the protein scientists want to observe in a given cell. The glowing protein is then attached to the target protein and zapped with a laser so it reaches a state of superposition, turning it into a nano-probe that picks up what is happening in the cell. From there, scientists can infer how a certain biological process happens, what the beginnings of a genetic disease look like, or how cells respond to certain treatments.

And eventually, this kind of sensing could be used in non-biological applications as well.

“Directed evolution on our EYFP qubit could be used to optimize its optical and spin properties and even reveal unexpected insights into qubit physics,” the researchers said. “Protein-based qubits are positioned to take advantage of techniques from both quantum information sciences and bioengineering, with potentially transformative possibilities in both fields.”

Superradiance Discovery Extends Quantum Entanglement Range 17-Fold

When the light field becomes more uniform, all the atoms find themselves optically close to each other, even if they are spatially distant. In other words, the “ambient” near-zero refractive index relaxes the strict distance between the atoms’ positions, an essential condition for the entanglement of quantum particles. Quantum entanglement corresponds to correlations between particles, essential for the development of information and quantum computers.

From electrodynamics to quantum computing

This is where the promising contribution of a team of researchers from UNamur, Harvard and Michigan Technological University (MTU) comes in, supported by Dr. Larissa Vertchenko, from Danish quantum technology company Sparrow Quantum. Adrien Debacq, FNRS aspirant researcher at the Namur Institute of Structured Matter (NISM) and co-author of the paper, assisted by Harvard PhD student Olivia Mello and Dr Larissa Vertchenko, have together theoretically developed a photonic chip capable of radically improving the range of entanglement between transmitters, up to 17 times greater than in a vacuum.

Quantum Computing Meets Finance

Eric Ghysels made a name for himself in financial econometrics and time-series analysis. Now he translates financial models into quantum algorithms.

Economist Eric Ghysels has spent most of his career fascinated by a fundamental problem in the financial industry: figuring out how to put a price on any financial asset whose future value depends on market conditions. Ghysels, a professor at the University of North Carolina at Chapel Hill, has now set himself a new problem: studying the impact that quantum computing could have on solving asset pricing, portfolio optimization, and other computationally intensive financial problems.

He admits that nobody knows when quantum computers will have commercially viable applications, but, he says, it’s important to invest now. Physics Magazine spoke with Ghysels to learn why.

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