A proposed experiment could bring scientists closer to answering the long-standing question of whether gravity is a classical or a quantum phenomenon.
Category: quantum physics – Page 303
Shedding Light on the Thorium-229 Nuclear Clock Isomer
Researchers use a laser to excite and precisely measure a long-sought exotic nuclear state, paving the way for precise timekeeping and ultrasensitive quantum sensing.
Any reliably produced, periodic phenomenon—from the swing of a pendulum to the vibrations of a single atom—can form the basis of a clock. Today’s most precise timekeeping is based on extremely narrow electronic transitions in atoms, which resonate at optical frequencies. These stupendously precise optical atomic clocks lose just 1 second (s) in about 30 billion years. However, they could potentially be outperformed by a nuclear clock, which would instead “tick” to the resonant frequency of a transition that occurs in the atomic nucleus instead of in the electronic shell. The most promising candidate for this nuclear standard is an exceptionally low-energy and long-lived excited state, or isomer, of the isotope thorium-229 (229 Th). Researchers have now achieved the long-sought goal of exciting this transition with ultraviolet light.
Twisting and binding matter waves with photons in a cavity
Precisely measuring the energy states of individual atoms has been a historical challenge for physicists due to atomic recoil. When an atom interacts with a photon, the atom “recoils” in the opposite direction, making it difficult to measure the position and momentum of the atom precisely. This recoil can have big implications for quantum sensing, which detects minute changes in parameters, for example, using changes in gravitational waves to determine the shape of the Earth or even detect dark matter.
Physicists arrange atoms in close proximity, paving way for exploring exotic states of matter
MIT physicists have developed a technique that allows them to arrange atoms in much closer proximity, down to a mere 50 nanometers.
Proximity is key for many quantum phenomena, as interactions between atoms are stronger when the particles are close. In many quantum simulators, scientists arrange atoms as close together as possible to explore exotic states of matter and build new quantum materials.
Intel Takes Next Step Toward Building Scalable Silicon-Based Quantum Processors
Research published in Nature demonstrates high qubit control fidelity and uniformity in single-electron control.
SANTA CLARA, Calif., May 1, 2024 —(BUSINESS WIRE)—Today, Nature published an Intel research paper, “Probing single electrons across 300-mm spin qubit wafers,” demonstrating state-of-the-art uniformity, fidelity and measurement statistics of spin qubits. The industry-leading research opens the door for the mass production and continued scaling of silicon-based quantum processors, all of which are requirements for building a fault-tolerant quantum computer.
Quantum hardware researchers from Intel developed a 300-millimeter cryogenic probing process to collect high-volume data on the performance of spin qubit devices across whole wafers using complementary metal oxide semiconductor (CMOS) manufacturing techniques.
Physicists build new device that is foundation for quantum computing
Scientists have adapted a device called a microwave circulator for use in quantum computers, allowing them for the first time to precisely tune the exact degree of nonreciprocity between a qubit, the fundamental unit of quantum computing, and a microwave-resonant cavity. The ability to precisely tune the degree of nonreciprocity is an important tool to have in quantum information processing. In doing so, the team derived a general and widely applicable theory that simplifies and expands upon older understandings of nonreciprocity so that future work on similar topics can take advantage of the team’s model, even when using different components and platforms.
Generating graph states of atomic ensembles via photon-mediated entanglement
Graph states, a class of entangled quantum states that can be represented by graphs, have been the topic of numerous recent physics studies, due to their intriguing properties. These unique properties could make them particularly promising for quantum computing applications, as well as a wider range of quantum technologies.
