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Category: quantum physics – Page 10

Quantum simulator reveals how vibrations steer energy flow in molecules

Researchers led by Rice University’s Guido Pagano used a specialized quantum device to simulate a vibrating molecule and track how energy moves within it. The work, published Dec. 5 in Nature Communications, could improve understanding of basic mechanisms behind phenomena such as photosynthesis and solar energy conversion.

The researchers modeled a simple two-site molecule with one part supplying energy and the other receiving it, both shaped by vibrations and their environment. By tuning the system, they could directly observe energy moving from donor to acceptor and study how vibrations and energy loss influence that transfer, providing a controlled way to test theories of energy flow in complex materials.

“We can now observe how energy moves in a synthetic molecule while independently adjusting each variable to see what truly matters,” said Pagano, assistant professor of physics and astronomy.

The Quantum Security Problem No One Is Ready For

Quantum computers are expected to deliver dramatic gains in processing speed and capability, with the potential to reshape fields ranging from scientific research to commercial innovation.

However, those same advantages could also make these machines attractive targets for cyberattacks, according to Swaroop Ghosh, a professor of computer science and electrical engineering at the Penn State School of Electrical Engineering and Computer Science.

Ghosh and co-author Suryansh Upadhyay, who recently earned his doctorate in electrical engineering from Penn State, examined these concerns in a new research paper that outlines key security weaknesses in current quantum computing systems. Published in the Proceedings of the Institute of Electrical and Electronics Engineers (IEEE), the study argues that protecting quantum computers will require more than software safeguards, emphasizing the importance of securing the underlying hardware as well.

Quantum-dot device can generate multiple frequency-entangled photons

Researchers have designed a new device that can efficiently create multiple frequency-entangled photons, a feat that cannot be achieved with today’s optical devices. The new approach could open a path to more powerful quantum communication and computing technologies.

“Entangling particles efficiently is a critical capability for unlocking the full power of quantum technologies—whether to accelerate computations, surpass fundamental limits in precision measurement, or guarantee unbreakable security using the laws of quantum physics,” said Nicolas Fabre from Telecom Paris at the Institut Polytechnique de Paris.

“Photons are ideal because they can travel long distances through optical fibers or free space; however, there hasn’t been a way to efficiently generate frequency entanglement between more than two photons.”

Negative Energy ‘Ghosts’ Flashing in Space Could Reveal New Physics

A ‘boom’ of light that appears when a particle exceeds the speed of light set by a medium could, in other contexts, signal a kind of quantum instability that could trigger what’s known as vacuum decay.

If ever spotted in the emptiness of space, according to theoretical physicist Eugeny Babichev of the University of Paris-Saclay, the eerie blue glow of Cherenkov radiation could be interpreted as a manifestation of negative-energy ghost perturbations.

Why does it matter? Because our current theory of gravity is incomplete, and such a signal would offer rare insight into how spacetime behaves in regimes where existing theories break down, and potentially narrow the search for better models.

Scientists realize a three-qubit quantum register in a silicon photonic chip

Quantum technologies are highly promising devices that process, transfer or store information leveraging quantum mechanical effects. Instead of relying on bits, like classical computers, quantum devices rely on entangled qubits, units of information that can also exist in multiple states (0 and 1) at once.

A research team at the University of California Berkeley (UC Berkeley) supervised by Alp Sipahigil recently demonstrated the potential of leveraging atomic-scale defects on silicon chips, known as T-centers, to create small multi-qubit memory units that store quantum information (i.e., quantum registers).

Their paper, published in Nature Nanotechnology, could open new possibilities for the development of quantum technologies that are based on silicon, which is the most widely used material within the electronics industry.

DNA Gene’s Basic Structure as a Nonperturbative Circuit Quantum Electrodynamics: Is RNA Polymerase II the Quantum Bus of Transcription?

Previously, we described that Adenine, Thymine, Cytosine, and Guanine nucleobases were superconductors in a quantum superposition of phases on each side of the central hydrogen bond acting as a Josephson Junction. Genomic DNA has two strands wrapped helically around one another, but during transcription, they are separated by the RNA polymerase II to form a molecular condensate called the transcription bubble. Successive steps involve the bubble translocation along the gene body. This work aims to modulate DNA as a combination of n-nonperturbative circuits quantum electrodynamics with nine Radio-Frequency Superconducting Quantum Interference Devices (SQUIDs) inside. A bus can be coupled capacitively to a single-mode microwave resonator. The cavity mode and the bus can mediate long-range, fast interaction between neighboring and distant DNA SQUID qubits.

The Dark Halo That Never Lit Up

Galaxies announce themselves through the light of billions of stars, all embedded in vast clumps, or “halos,” of dark matter. But researchers may have spotted, for the first time, a starless halo of dark matter—containing only a gas cloud. The result was announced by Rachael Beaton of the Space Telescope Science Institute in Maryland at the meeting of the American Astronomical Society in Phoenix, Arizona. Using observations from the Hubble Space Telescope, Beaton and her collaborators showed that the object, known as Cloud-9, contains a negligible amount of stars [1]. “There is nothing like this that we have found so far in the Universe,” Beaton said in a press conference last week.

Cloud-9’s makeup—as inferred from radio and optical observations—would qualify it as the first example of a REionization-Limited H I Cloud (RELHIC), a starless dark matter halo filled with neutral hydrogen gas (H I). RELHICs are thought to be leftovers of dark matter clumps that couldn’t accrue a sufficient amount of gas to form stars, says the project’s principal investigator Alejandro Benítez-Llambay of the University of Milano-Bicocca in Italy. A RELHIC is “a tale of a failed galaxy,” he says.

Starless halos arise naturally within the standard paradigm of cosmology: the lambda cold dark matter (ΛCDM) model, where Λ refers to a “cosmological constant” that describes dark energy. According to ΛCDM, dark matter can cluster into halos that provide the gravitational backbone for galaxy formation. The model also predicts that there is a critical mass below which halos would be too small to ever form stars. Spotting unlit halos might sound hopeless, but simulations by Benítez-Llambay and collaborators in 2017 suggested that halos within a narrow mass range may exist as RELHICs (a term they coined) [2]. According to their calculations, RELHICs would have masses close to the critical value for galaxy formation. Crucially, the compact, hydrogen-filled cores of these objects provide a potential observational window, since hydrogen clouds have a characteristic radio emission.

A new valve for quantum matter: Steering chiral fermions by geometry alone

A collaboration between Stuart Parkin’s group at the Max Planck Institute of Microstructure Physics in Halle (Saale) and Claudia Felser’s group at the Max Planck Institute for Chemical Physics of Solids in Dresden has realized a fundamentally new way to control quantum particles in solids. Writing in Nature, the researchers report the experimental demonstration of a chiral fermionic valve—a device that spatially separates quantum particles of opposite chirality using quantum geometry alone, without magnetic fields or magnetic materials.

The work was driven by Anvesh Dixit, a Ph.D. student in Parkin’s group in Halle, and the first author of the study, who designed, fabricated, and measured the mesoscopic devices that made the discovery possible.

“This project was only possible because we could combine materials with exceptional topological quality and transport experiments at the mesoscopic quantum limit,” says Anvesh Dixit. “Seeing chiral fermions separate and interfere purely due to quantum geometry is truly exciting.”

LANL: Los Alamos To Play Key Role In Renewed Quantum Science Center

PRESS RELEASE — The Department of Energy has renewed funding for the Quantum Science Center, with Los Alamos National Laboratory continuing to play a vital role along with Oak Ridge National Laboratory in the center’s mission to advance quantum science and technology. The center will be funded for $125 million over five years to focus on quantum-accelerated high-performance computing.

“The Quantum Science Center is establishing the scientific and technical foundation for quantum computing,” said Mark Chadwick, associate Laboratory director for Simulation, Computing and Theory. “In this new, critical evolution for the center, the integration of quantum and high-performance computing stands to accelerate advancements in crucial scientific areas related to technological progress and even national security applications.”

The Quantum Science Center combines the efforts of three national laboratories, with ORNL hosting the center and Los Alamos a principal partner alongside various universities, industry partners and other laboratories. Created as one of five National Quantum Information Science Research Centers supported by the DOE’s Office of Science, the Quantum Science Center seeks to create a scientific ecosystem for the advancement of fault-tolerant, quantum-accelerated high-performance computing.

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