In 1960, DARPA funded three university-based Inderdisciplinary Laboratories (IDLs) that opened the way toward an enormous field of research and development known today as materials science and engineering. In this video, DARPA program managers, DARPA-funded researchers, and a Naval Research Laboratory scientist tell this field-building story as it unfolded over the past six decades, all the while delivering breakthroughs in the way materials are designed, processed, and deployed to push technologies forward. Intelligent processing of materials (IPM), accelerated insertion of materials (AIM), and integrated computational materials engineering (ICME) are among the specific programs detailed in the video. DARPA is currently developing technologies that enable the crafting of new materials with unprecedented properties by designing and controlling matter from atoms on up to human-scale systems.
Category: particle physics – Page 229
Electrons Lead Their Lattice by the Nose
Experiments with an unconventional superconductor show that a change in the properties of the material’s electrons can, unexpectedly, cause the material to become dramatically less stiff.
Electrons flowing through a crystal lattice don’t usually get to call the shots: their behavior is generally set by the lattice structure. But certain materials exhibit an electron–lattice coupling that allows the conduction electrons to influence the lattice behavior. This electron version of “wagging the dog” is predicted to be quite weak, making it a surprise that experiments with an unconventional superconductor now uncover a large electron-driven softening of the material’s lattice [1]. The finding could provide new insights into the mechanisms underlying unconventional superconductivity.
The lattice in a crystalline material is a periodic framework of atoms held together by electrostatic bonds. That framework dictates the properties of electrons moving through the material. For example, if the lattice is altered by applying mechanical strain or by adding dopant atoms, the electron momenta will correspondingly change, which can affect the material’s electronic band structure.
Midcircuit Operations in Atomic Arrays
Three research groups have exploited the nuclear spins of ytterbium-171 to manipulate qubits before they are read out—an approach that could lead to efficient error-correction schemes for trapped-atom computing platforms.
Quantum computing on neutral-atom platforms has reached remarkable milestones in the past two decades. However, researchers have yet to overcome a key barrier to the realization of a neutral-atom-based quantum computer: the efficient correction of errors. In principle that barrier can be lowered with so-called midcircuit operations. These operations involve probing the quantum state of “ancilla” qubits without disturbing nearby “data” qubits used for computation. The ancilla qubit measurements can indicate whether the data qubits have undergone faulty operations, allowing for the data qubits to be corrected midcircuit—that is, during the execution of the computation rather than after its completion. Now three independent research groups have achieved midcircuit operation, or made progress toward this goal, with a novel choice of atom: ytterbium-171 (171 Yb) [1– 3].
A neutral-atom qubit platform consists of a two-dimensional (2D) array of atoms trapped by optical tweezers—tightly focused laser beams whose wavelengths are tuned far away from the atomic transitions. The size of the traps, limited by diffraction, is typically about 1 µm. Thanks to the large electric-dipole force from the focused laser and to a high vacuum, the atoms can stay trapped for as long as tens of seconds.
Uncertainty beyond the Uncertainty Principle
Heisenberg’s uncertainty principle limits the precision with which two observables that do not commute with each other can be simultaneously measured. The Wigner-Araki-Yanase (WAY) theorem goes further. If observables A and B do not commute, and if observable A is conserved, observable B cannot be measured with arbitrary precision even if A is not measured at all. In its original 1960 formulation, the WAY theorem applied only to observables, such as spin, whose possible values are discrete and bounded. Now Yui Kuramochi of Kyushu University and Hiroyasu Tajima of the University of Electro-Communications—both in Japan—have proven that the WAY theorem also encompasses observables, such as position, that are continuous and unbounded [1]. Besides resolving the decades-long problem of how to deal with such observables, the extension will likely find practical applications in quantum optics.
The difficulty of extending the WAY theorem arose from how an unbounded observable L is represented: as an infinite-dimensional matrix with unbounded eigenvalues. To tame the problem, Kuramochi and Tajima avoided considering L directly. Instead, they looked at an exponential function of L, which forms a one-parameter unitary group. Although the exponential function is also unbounded, its spectrum of eigenvalues is contained within the complex plane’s unit circle. Thanks to that boundedness, Kuramochi and Tajima could go on to use off-the-shelf techniques from quantum information to complete their proof.
Because momentum is conserved, the extended WAY theorem implies that a particle’s position cannot be measured with arbitrary precision even if its momentum is not measured simultaneously. Similar pairs of observables crop up in quantum optics. Kuramochi and Tajima anticipate that their theorem could be useful in setting limits on the extent to which quantum versions of transmission protocols can outperform the classical ones.
Quantum Riddle Solved: Purple Bronze Discovery Unveils “Perfect Switch” for Future Tech
Quantum scientists have discovered a phenomenon in purple bronze, a one-dimensional metal, that allows it to switch between insulating and superconducting states. This switch, triggered by minimal stimuli like heat or light, is due to ’emergent symmetry’. This groundbreaking finding, initiated by research into the metal’s magnetoresistance, could lead to the development of perfect switches in quantum devices, a potential milestone in quantum technology.
Quantum scientists have discovered a phenomenon in purple bronze that could be key to the development of a ‘perfect switch’ in quantum devices which flips between being an insulator and superconductor.
The research, led by the University of Bristol and published in Science, found these two opposing electronic states exist within purple bronze, a unique one-dimensional metal composed of individual conducting chains of atoms.
Unraveling the Mysteries of ϕ Mesons: A New Breakthrough in Heavy-Ion Collision Physics
A team of researchers headed by Prof. Wang Qun at the University of Science and Technology of China, under the Chinese Academy of Sciences, has achieved a breakthrough in the theoretical understanding of vector meson spin physics, focusing on the unique properties of ϕ mesons produced during collisions between gold nuclei.
Their findings published in the journal Physical Review Letters
Physical Review Letters (PRL) is a peer-reviewed scientific journal published by the American Physical Society. It is one of the most prestigious and influential journals in physics, with a high impact factor and a reputation for publishing groundbreaking research in all areas of physics, from particle physics to condensed matter physics and beyond. PRL is known for its rigorous standards and short article format, with a maximum length of four pages, making it an important venue for rapid communication of new findings and ideas in the physics community.
First experimental evidence of hopfions in crystals: Research opens up new dimension for future technology
Hopfions, magnetic spin structures predicted decades ago, have become a hot and challenging research topic in recent years. In a study published in Nature, the first experimental evidence is presented by a Swedish-German-Chinese research collaboration.
“Our results are important from both a fundamental and applied point of view, as a new bridge has emerged between experimental physics and abstract mathematical theory, potentially leading to hopfions finding an application in spintronics,” says Philipp Rybakov, researcher at the Department of Physics and Astronomy at Uppsala University, Sweden.
A deeper understanding of how different components of materials function is important for the development of innovative materials and future technology. The research field of spintronics, for example, which studies the spin of electrons, has opened up promising possibilities to combine the electrons’ electricity and magnetism for applications such as new electronics.
Research reveals rare metal could offer revolutionary switch for future quantum devices
Quantum scientists have discovered a rare phenomenon that could hold the key to creating a ‘perfect switch’ in quantum devices which flips between being an insulator and a superconductor.
The research, led by the University of Bristol and published in Science, found these two opposing electronic states exist within purple bronze, a unique one-dimensional metal composed of individual conducting chains of atoms.
Tiny changes in the material, for instance, prompted by a small stimulus like heat or light, may trigger an instant transition from an insulating state with zero conductivity to a superconductor with unlimited conductivity, and vice versa. This polarized versatility, known as “emergent symmetry,” has the potential to offer an ideal On/Off switch in future quantum technology developments.
The Importance of the Earth’s Atmosphere in Creating the Large storms that Affect Satellite Communications
A study from an international team led by researchers from Nagoya University in Japan and the University of New Hampshire in the United States has revealed the importance of the Earth’s upper atmosphere in determining how large geomagnetic storms develop. Their findings reveal the previously underestimated importance of the Earth’s atmosphere. Understanding the factors that cause geomagnetic storms is important because they can have a direct impact on the Earth’s magnetic field such as causing unwanted currents in the power grid and disrupting radio signals and GPS. This research may help predict the storms that will have the greatest consequences.
Scientists have long known that geomagnetic storms are associated with the activities of the Sun. Hot charged particles make up the Sun’s outer layer, the one visible to us. These particles flow out of the Sun creating the ‘solar wind’, and interact with objects in space, such as the Earth. When the particles reach the magnetic field surrounding our planet, known as the magnetosphere, they interact with it. The interactions between the charged particles and magnetic fields lead to space weather, the conditions in space that can affect the Earth and technological systems such as satellites.
An important part of the magnetosphere is the magnetotail. The magnetotail is the part of the magnetosphere that extends away from the Sun, in the direction of the solar wind flow. Inside the magnetotail is the plasma sheet region, which is full of charged particles (plasma). The plasma sheet is important because it is the source region for the particles that get into the inner magnetosphere, creating the current that causes geomagnetic storms.