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Physicists prove a long-suspected quantum speed limit for thermalization

Whether we are waiting for a car windshield to defrost in winter or a warm drink to cool down, how long it takes for an object to settle into a stable, even temperature within its environment (thermal equilibrium) depends on numerous factors. These can include surface area, the material properties of an object and airflow.

But when we zoom down to the subatomic scale, such as where qubits operate in a quantum computer, a different set of rules takes over. External conditions still matter, but according to a new paper published in the journal Nature Physics, quantum mechanics sets a fundamental speed limit on how quickly a process can bring different quantum systems into thermal equilibrium.

What makes the finding significant is that this boundary is universal. No matter how much energy is applied or how strongly a system is manipulated, the process cannot be forced to go any faster.

New monolithic ion trap opens quantum simulations to more researchers

Some quantum systems are so complex that even the most powerful supercomputers struggle to simulate their behavior. One solution is quantum simulation: building a controllable quantum system in the lab and tuning it to mimic the one researchers want to understand.

In a trapped-ion simulator, a row of individual charged atoms, or ions, is held in place by electric fields inside a device called an ion trap. Lasers are used to make the ions interact in a manner that simulates the quantum system, and then researchers measure the information encoded in the ions to reveal the system’s properties.

Rice University’s Guido Pagano, along with collaborators at Duke University and Translume Inc., has developed a new kind of trapped-ion simulator, called a monolithic segmented 3D ion trap. This trap allowed the team to study these complex systems using heavy ions like ytterbium.

Hybrid diamond chip strengthens interactions between light and quantum bits

Researchers have developed and demonstrated a new hybrid photonic platform that integrates quantum emitters with photonic devices, providing a way to reliably control the interaction between photons and quantum information carriers. The chip-based platform, which combines gallium phosphide (GaP) with a diamond substrate, could help make quantum networks more practical by providing a way to connect quantum devices over long distances.

Scaling up quantum technology to create communication networks requires connecting quantum memories, or qubits, over long distances. Although fiber-optic networks offer a promising way to do this using optical signals, a key challenge is reliably converting information stored in qubits into optical photons that can travel through the network.

“We show that our hybrid-integrated GaP-on-diamond nanophotonic platform can address this challenge by realizing reliably controlled interactions between photons and a type of qubit called a silicon-vacancy (SiV) center in diamond,” said the paper’s first author, Nicholas S. Yama from the University of Washington. “GaP also has strong nonlinear properties that enable optical frequency conversion, switching and modulation, all of which are needed for networking applications.”

A new way to detect stabilizing properties of optical devices

In optical fibers, chips and other light-guiding devices, minor defects can scatter photons and disrupt their path. A new study demonstrates a way to reveal properties which, in certain systems, help light wave behavior withstand such flaws. The method could help speed up the search for new kinds of electronics and optical technologies, and contribute to more reliable quantum devices.

Reporting in Physical Review Letters, researchers at KTH Royal Institute of Technology demonstrate a programmable chip that can detect and measure “topological properties,” or features of wave behavior that don’t change even when a system is altered.

KTH Associate Professor Ali Elshaari says understanding these properties can help devices keep working despite imperfections.

What Kills Schrödinger’s Cat? Scientists Just Ruled Out a 60-Year-Old Theory

Gravity has been proposed as a reason quantum superpositions become difficult to observe in everyday objects. A new experiment challenges one longstanding model of this process.

A detector buried deep beneath an Italian mountain has challenged a decades-old theory about why quantum behavior disappears from the world we experience. After 62 days of measurements, researchers found no trace of the faint radiation predicted by a model in which gravity disrupts quantum states. The result rules out this particular explanation while leaving open the possibility that gravity contributes to quantum decoherence.

Decoherence helps explain why particles can display unusual quantum behavior, such as existing in superpositions of different states, while everyday objects appear to follow classical physics. “One of the deepest questions in modern physics is why the strange quantum behavior that governs atoms and elementary particles seems to disappear in the macroscopic world we experience every day,” says Catalina Curceanu, director of research and spokesperson for the VIP Collaboration at the National Laboratory of Frascati of the National Institute for Nuclear Physics (INFN-LNF) in Italy.

Scientists Turn Ordinary Plastic Into Billions of Tiny Diamonds Using Powerful Lasers

Diamonds recovered from plastic contain roughly 3,000 atoms each and could be modified with other elements for future use in medical imaging.

Powerful lasers can turn plastic into tiny diamonds, but recovering the crystals means catching them as they shoot out at speeds comparable to a meteorite impact. Researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and the University of Rostock have now collected those diamonds intact, showing that they survive the return from extreme pressure and temperature to ordinary conditions.

The recovered particles averaged three nanometers across, or three billionths of a meter, with roughly 3,000 carbon atoms in each diamond. The laser technique produces a combination of high purity, exceptionally small size, and closely matched particle sizes that conventional methods, including explosions, cannot achieve.

Researchers Unleash Record-Breaking X-Ray Flashes in Just 300 Attoseconds

Researchers used the European XFEL to produce ultrashort X-ray flashes that reached record intensity for this type of pulse.

To understand chemical reactions and perhaps one day control the electrons involved, scientists need a detailed picture of how electrons behave inside atoms and molecules. X-rays offer a way to probe that behavior, but the flashes can also change the sample they are meant to examine. Researchers therefore need enough light to gather useful information before those changes become substantial.

At the European XFEL, a team has now concentrated X-ray flashes onto an area roughly 100,000 times smaller than the cross-section of a typical human hair. The pulses lasted an estimated 300 attoseconds, with each attosecond equal to a billionth of a billionth of a second.

NASA’s James Webb Telescope Reveals a Giant Alien Planet That’s Not Quite Round

Weather maps of distant planets are a step closer after the James Webb Space Telescope distinguished hotter and cooler regions around the giant exoplanet WASP-17b.

One side of WASP-17b’s atmosphere extends farther into space than the other, giving this intensely hot giant planet an uneven outline. Astronomers have now mapped that distortion with the James Webb Space Telescope (JWST), finding a pattern consistent with predictions of how heat and powerful winds shape a world with permanent day and night sides.

WASP-17b is a hot Jupiter, a giant planet that orbits close to its star, about 1,300 light-years from Earth. The study, co-led by Cornell University in the United States and the University of Bristol in the United Kingdom, was published in Nature Astronomy. It marks the first application of a method called transmission strings, developed at Bristol by astrophysicists Dr. David Grant and Dr. Hannah Wakeford.

Quantum Computing Breakthrough Opens a New Path to Larger, More Powerful Processors

Keeping silicon quantum bits accurate while they work together could help turn established chipmaking technology into larger quantum computers capable of tackling increasingly complex problems.

The manufacturing technology behind everyday computer chips could help build larger quantum computers. Silicon spin qubits offer that possibility, but the precision they achieve on their own can slip when several are controlled at once.

Researchers from the RIKEN Center for Emergent Matter Science and their collaborators have now demonstrated a way to preserve much of that precision during simultaneous operation. Working with five silicon qubits controlled through a single shared microwave line, they identified a major source of control errors and developed a calibration protocol to compensate for it. Their study was published in Nature Physics.

Scientists Discover Metals That Refuse To Crack at an Astonishing —424°F

Two experimental alloys resisted cracking at −424°F by forming new crystal defects, offering a possible route to tougher metals for extreme cold.

Most metals become stronger as they cool, but some also become more vulnerable to breaking. Iron, tungsten, and chromium belong to a class called body-centered cubic metals, whose atomic arrangement can make them increasingly brittle as temperatures fall. A crack that the metal might otherwise accommodate by bending or stretching can instead cause a fracture.

That ability to deform depends heavily on the movement of dislocations, line-like defects in the metal’s crystal structure. At low temperatures, these defects become harder to move, limiting how much the material can deform to relieve the forces building up around a crack.