Materials in a quantum state come with exotic properties that bend the laws of physics and offer huge potential to scientists – but they’re usually also incredibly delicate, and require ultra-low temperatures to exist and function.
That presents a problem when it comes to making the most of these materials and their characteristics: they need to move out of large lab refrigerators.
We’re now another step towards that being possible.
The Sachdev-Ye-Kitaev (SYK) model describes information scrambling in black holes and an unusual metallic phase in high-temperature superconductors. Despite those and other far-reaching applications, realizing the model in the lab has been extremely challenging because the particle interactions required are intricate and long-ranged. Now Charles Creffield at the Complutense University of Madrid and his colleagues have detailed how this model could be simulated in existing cold-atom setups [1]. Their strategy provides a practical path to exploring quantum phenomena that are currently confined to theory.
Rather than engineer the requisite particle interactions from the outset, the team started with a much simpler setup emulating the Hubbard model, which is used to understand how electrons moving in a lattice give rise to superconductivity and other phenomena. Ultracold atoms are placed in a one-dimensional optical lattice, where they hop between lattice sites and mutually repel each other when occupying the same site. The lattice is then periodically shaken to make the rate of hopping oscillate in time. This modulation suppresses the atoms’ ordinary motion and generates effective interactions between all the atoms at once, closely resembling the particle behavior of the SYK model.
Using detailed numerical simulations, the researchers went on to show that their Hubbard-based system reproduces several key features of the SYK model, including its characteristic chaotic dynamics and fast spreading of quantum information. The team emphasizes that its approach could be enacted straightforwardly using currently available cold-atom technologies. Such an implementation would offer a controlled, versatile platform for simulating the SYK model and possibly for probing the uncertain physics of quantum chaos and quantum gravity.
A diamagnetic substance is slightly repelled by magnetic fields. With a strong enough magnet, the diamagnetic force can override gravity, and the substance will float in the air. Graphite, the main component of pencil lead, is considered one of the best substances for such real-world levitation, and its potential application in sensing weak external perturbations is drawing growing interest.
Until recently, graphite’s electrical conductivity posed an obstacle because electric currents suppress this levitation. Previous research found that a glass coating efficiently blocks the current but also causes the particles to point in all directions, weakening the lifting force.
A team of researchers at Kyoto University happened to be developing a possible solution: making single-crystal equivalents of various substances from fine powders by aligning microcrystals in a uniform direction. Though the scientists specialize in nuclear magnetic resonance spectroscopy, once they came across the graphite levitation issue, they realized they could make a substantial contribution to solving this conundrum.
Scientists at the University of California, Riverside, have developed a new way to help gravitational-wave observatories see farther into the universe by solving one of their biggest challenges: tiny heat-induced distortions in the massive mirrors at the heart of the detectors.
The technique, described in a paper published in Classical and Quantum Gravity, uses thermal imaging to reveal microscopic distortions caused by powerful lasers. By measuring those distortions more precisely, observatories such as the Laser Interferometer Gravitational-Wave Observatory (LIGO) could improve their sensitivity and detect weaker, more distant gravitational-wave events.
The goal for the next generation of gravitational-wave detectors is to achieve about 10 times the sensitivity of today’s instruments,” said Jonathan Richardson, an associate professor of physics and astronomy at UC Riverside who led the study. “One of the key obstacles to achieving that is reducing the fundamental quantum-mechanical noise that limits the precision of the measurements.”
A black hole may be stirring a “pot” of gas containing a neighboring galaxy in the early universe, according to a new study published in Astronomy & Astrophysics that used observations from NASA’s Chandra X-ray Observatory. The galaxy slowly being “cooked” is named MQN01 J004131.9–493704, but astronomers have nicknamed it the “red potato” because of its appearance in images from NASA’s James Webb Space Telescope.
The red potato galaxy is located about 11.7 billion light-years from Earth at an intersection where gigantic web-like structures of galaxies and gas meet. Astronomers targeted this area with Webb because they knew it contained one of the heaviest concentrations of galaxies and growing supermassive black holes yet identified in the early universe.
Researchers in China have unveiled a new robotic exosuit driven entirely by soft artificial muscles instead of traditional motors. This technology could make it easier for older adults, injured patients or factory workers to walk with much less effort. Current exosuits that aid walking use heavy motors, gearboxes and noisy air-pressure pumps that restrict a person’s natural movement.
Soft muscles, on the other hand, are made of thin, flexible rubber fibers that behave more like human muscles and are considerably lighter, making it easier for people to move.
Details of the work are in a paper published in the journal Science Advances.
The star that formed the Jellyfish nebula may have had a partner star that exploded 100,000 years earlier, according to international researchers, who say that this may be the first known discovery of a binary star system in which both stars have gone supernova.
The Jellyfish nebula, known as IC 443, is the remnant of a star exploding in a supernova and leaving behind an expanding cloud of debris. IC 443 is located in the Gemini constellation, approximately 6,000 light-years from Earth, and researchers have now discovered that it occupies the same physical environment as another supernova remnant called G189.6+3.3. The findings are published in the journal Nature Communications.
Supernova remnants are expanding clouds of debris left behind after supernovae (stellar explosions). While hundreds of such remnants are known in our galaxy, identifying relationships between them is difficult, particularly in crowded regions of the Milky Way. IC 443, a remnant in the constellation Gemini approximately 6,000 light-years from Earth, sits close to other astronomical structures and within a complex cloud of gas and dust, making its surrounding region difficult to study.
One of the deepest ambitions in modern physics is understanding how the fabric of space and time could emerge from fundamental quantum degrees of freedom to establish a quantum theory of gravity.
In the new paper, “Observation of gravity-like signatures in holographic codes on a quantum computer,” posted to the arXiv preprint server, researchers from the National Quantum Laboratory (QLab@UMD), the Duke Quantum Center, the Virginia Tech Center for Quantum Information Science and Engineering, Caltech’s Institute for Quantum Information and Matter, IonQ and BlueQubit have successfully simulated toy models of quantum gravity according to the AdS/CFT correspondence. The team, led by Crystal Noel and Charles Cao, includes quantum-computation pioneers John Preskill and Christopher Monroe.
Using the IonQ Forte ion-trap quantum computer, the study implements the intriguing HaPPY quantum error-correction code, which forms a bridge between quantum computing and quantum gravity. This code simulates a highly simplified model of a universe with a negative cosmological constant that features a so-called bulk-boundary correspondence, in which the properties of a higher-dimensional gravitational universe (bulk) are completely determined by a lower-dimensional quantum system without gravity living on the boundary. The team successfully demonstrated fundamental entanglement properties of these systems.
Researchers have developed a new type of optical fiber by freezing a glass capillary filled with liquid. It guides light and sound waves simultaneously and enables highly efficient coupling between them. The high coupling strength lowers the energy consumption of photonic neuromorphic computing schemes and quantum signal processing applications by several orders of magnitude.
When volcanoes erupt, one can observe streams of liquid lava cool and solidify into rock formations at the bottoms of volcanoes. The same physical process—a liquid changing into a solid phase upon cooling—can be observed when lakes start freezing during cold winters. These phase changes always come with changes in the physical properties of the material, such as the density or refractive index that govern how sound and light move through it.
This fundamental physical process is also used during the melting of glass preforms to loosen their structure while drawing optical fiber. These fibers then guide light through their cores, allowing the transmission of information via light very quickly over long distances, which is why they are widely used for telecommunications applications.
Stars and galaxies make up much of the universe’s ordinary, observable matter. But for decades, scientists have wrestled with a cosmic conflict: There should be much more.
Physicists have good estimates of how much matter was present in the early universe. Shortly after the Big Bang, roughly 83% of all matter in the universe was composed of invisible dark matter, with ordinary matter making up the rest. And yet, these estimates exceed the amount of ordinary matter seen in stars and galaxies today. Where, then, did all the missing ordinary matter go?
Now MIT scientists, as part of the CHIME/FRB Collaboration, are using far-off radio signals to reveal missing matter in the vast space between galaxies. The team has developed a new method to search out missing matter by combining locations of galaxies with detections of fast radio bursts.