Failing to see any high-energy neutrinos allowed researchers to calculate an upper limit on the fraction of high-energy cosmic rays that are protons.
Category: particle physics – Page 26
Scientists detect new ‘quantum echo’ in superconducting materials
Scientists at the U. S. Department of Energy Ames National Laboratory and Iowa State University have discovered an unexpected “quantum echo” in a superconducting material. This discovery provides insight into quantum behaviors that could be used for next-generation quantum sensing and computing technologies.
Superconductors are materials that carry electricity without resistance. Within these superconductors are collective vibrations known as “Higgs modes.” A Higgs mode is a quantum phenomenon that occurs when its electron potential fluctuates in a similar way to a Higgs boson. They appear when a material is undergoing a superconducting phase transition.
Observing these vibrations has been a long-time challenge for scientists because they exist for a very short time. They also have complex interactions with quasiparticles, which are electron-like excitations that emerge from the breakdown of superconductivity.
Terabytes of data in a tiny crystal
From punch card-operated looms in the 1800s to modern cellphones, if an object has “on” and “off” states, it can be used to store information.
In a laptop computer, the ones and zeroes that make up the binary language are actually transistors either running at low or high voltage. On a compact disc, the one is a spot where a tiny indented “pit” turns to a flat “land” or vice versa, while a zero represents no change.
Historically, the size of the object cycling through those states has put a limit on the size of the storage device. But now, researchers from the University of Chicago Pritzker School of Molecular Engineering have explored a technique to make the metaphorical ones and zeroes out of crystal defects, each the size of an individual atom, for classical computer memory applications.
UChicago researchers created a ‘quantum-inspired’ revolution in microelectronics, storing classical computer memory in crystal gaps where atoms should be.
Optimizing Diamond as a Quantum Sensor
Two independent groups optimize diamond-based quantum sensing by using more than 100 such sensors in parallel.
Diamond has long been prized for its beauty, and it holds the record as the hardest known natural material. By introducing nitrogen atoms into its crystal lattice, it can also be transformed into a remarkable quantum sensor. The associated crystal defects are known as nitrogen-vacancy (NV) centers, and they imbue such sensors with unprecedented electromagnetic-field sensitivity and excellent spatial resolution [1]. However, experimental platforms designed to exploit these sensors have so far had limited applicability because the sensing speed and resolution are difficult to simultaneously optimize. Now two research teams—one led by Shimon Kolkowitz at the University of California, Berkeley, [2] and the other by Nathalie de Leon at Princeton University [3]—have independently developed a way of manipulating and measuring more than 100 NV centers in parallel (Fig. 1).
Neutrinos could have a secret life: Study suggests they may interact secretly during massive star collapse
Neutrinos are cosmic tricksters, paradoxically hardly there but lethal to stars significantly more massive than the sun.
These elementary particles come in three known “flavors”: electron, muon and tau. Whatever the flavor, neutrinos are notoriously slippery, and much about their properties remains mysterious. It is almost impossible to collide neutrinos with each other in the lab, so it is not known if neutrinos interact with each other according to the standard model of particle physics, or if there are much-speculated “secret” interactions only among neutrinos.
Now a team of researchers from the Network for Neutrinos, Nuclear Astrophysics, and Symmetries (N3AS), including several from UC San Diego, have shown, through theoretical calculations, how collapsing massive stars can act as a “neutrino collider.” Neutrinos steal thermal energy from these stars, forcing them to contract and causing their electrons to move near light speed. This drives the stars to instability and collapse.
The dark side of time: Scientists develop nuclear clock method to detect dark matter using thorium-229
For nearly a century, scientists around the world have been searching for dark matter—an invisible substance believed to make up about 80% of the universe’s mass and needed to explain a variety of physical phenomena. Numerous methods have been used in attempts to detect dark matter, from trying to produce it in particle accelerators to searching for cosmic radiation that it might emit in space.
Yet even today, very little is known about this matter’s fundamental properties. Although it operates in the background, dark matter is believed to influence visible matter, but in ways so subtle that they currently cannot be directly measured.
Scientists believe that if a nuclear clock is developed—one that uses the atomic nucleus to measure time with extreme precision —even the tiniest irregularities in its ticking could reveal dark matter’s influence. Last year, physicists in Germany and Colorado made a breakthrough toward building such a clock, using the radioactive element thorium-229.
Researchers demonstrate error-resistant quantum gates using exotic anyons for computation
The quantum computing revolution draws ever nearer, but the need for a computer that makes correctable errors continues to hold it back.
Through a collaboration with IBM led by Cornell, researchers have brought that revolution one step closer, achieving two major breakthroughs. First, they demonstrated an error-resistant implementation of universal quantum gates, the essential building blocks of quantum computation. Second, they showcased the power of a topological quantum computer in solving hard problems that a conventional computer couldn’t manage.
In the article “Realizing String-Net Condensation: Fibonacci Anyon Braiding for Universal Gates and Sampling Chromatic Polynomials” published in Nature Communications, an international collaboration between researchers at IBM, Cornell, Harvard University and the Weizman Institute of Science demonstrated, for the first time, the ability to encode information by braiding—moving in a particular order—Fibonacci string net condensate (Fib SNC) anyons, which are exotic quasi-particles, in two dimensional space.
Scientists unveil new way to control magnetism in super-thin materials
A powerful new method to control magnetic behavior in ultra-thin materials could lead to faster, smaller and more energy-efficient technologies, a study suggests.
Researchers have developed a new way to precisely tune magnetism using a material—called CrPS4—that is just a few atoms thick. The study is published in the journal Nature Materials.
The advance could solve a long-standing scientific problem and pave the way for the development of new smart magnetic technologies, from computer memory devices to next-generation electronics, the team says.
A new mechanism to realize spin-selective transport in tungsten diselenide
Spintronics are promising devices that work utilizing not only the charge of electrons, like conventional electronics, but also their spin (i.e., their intrinsic angular momentum). The development of fast and energy-efficient spintronic devices greatly depends on the identification of materials with a tunable spin-selective conductivity, which essentially means that engineers can control how electrons with different spin orientations move through these materials, ideally using external magnetic or electric fields.