Phys.org July 29, 2022 Many of the most promising short-term applications of quantum computers fall under the umbrella of quantum simulation: modelling the quantum properties of microscopic particles that are directly relevant to modern materials science, high-energy physics, and quantum chemistry. This would impact several important real-world applications, such as developing materials for batteries, industrial catalysis or nitrogen fixing. Quantum simulation can be performed not only on future fault-tolerant digital quantum computers but also through special-purpose analogue quantum simulators. An international team of researchers (UK, Germany, Austria, USA – industry) has provided an overview of the state of the art […]
Tag Archives: Quantum technology
Scientists invent ‘quantum flute’ that can make particles of light move together
Nanowerk July 7, 2022 Because of the combination of long coherence times and large interaction strengths, one of the leading experimental platforms for cavity QED involves coupling a superconducting circuit to a 3D microwave cavity. In this work. An international team of researchers (USA – University of Chicago, University Rutgers, University of Chicago, UC Berkeley, South Korea) demonstrated a variety of protocols for universal single-mode quantum control applicable across all cavity modes, using only a single drive line. They achieved this by developing a straightforward flute method for creating monolithic superconducting microwave cavities that reduces loss while simultaneously allowing control […]
Quantum network nodes with warm atoms
Science Daily June 24, 2022 An international team of researchers (Switzerland, Germany) built and successfully interfaced a single-photon source based on cavity-enhanced spontaneous parametric down-conversion in periodically poled potassium titanyl phosphate and a matched memory based on electromagnetically induced transparency in warm 87Rb vapor. The bandwidth of the photons emitted by the source was 370MHz, which is within the accepted bandwidth of the memory. The experimental complexity was kept low, with all components operating at or above room temperature. Read-out noise of the memory was considerably reduced by exploiting polarization selection rules in the hyperfine structure of spin-polarized atoms. They […]
A Huge Step Forward in Quantum Computing Was Just Announced: The First-Ever Quantum Circuit
Science Alert June 22, 2022 Researchers in Australia have created a functional quantum processor and tested it by modeling a small molecule in which each atom has multiple quantum states. They used a scanning tunneling microscope in an ultra-high vacuum to place quantum dots with sub-nanometer precision. The trickiest parts were figuring out: exactly how many atoms of phosphorus should be in each quantum dot; exactly how far apart each dot should be; and then engineering a machine that could place the tiny dots in exactly the right arrangement inside the silicon chip. The final quantum chip contained 10 quantum […]
Improving quantum sensors by measuring the orientation of coherent spins inside a diamond lattice
Phys.org June 16, 2022 Researchers in Japan have developed a new method for implementing magnetic field measurements in nitrogen-vacancy centers. The spin state of an extra electron at this site can be read or coherently manipulated using pulses of light. They used an “inverse Cotton-Mouton” effect to test their method. They used light of different polarizations to create tiny controlled local magnetic fields. They have demonstrated that by measuring the orientation of coherent spins inside a diamond lattice, the magnetic fields can be measured even over very short times. The team hopes that this work will help enable quantum spintronic […]
Emulating impossible ‘unipolar’ laser pulses paves the way for processing quantum information
Science Daily May 24, 2022 Key applications such as THz scanning tunnelling microscopy or electronic devices operating at optical clock rates call for ultimately short, almost unipolar waveforms, at megahertz (MHz) repetition rates. An international team of researchers (Germany, USA – University of Michigan) has developed a flexible and scalable scheme for the generation of strong phase-locked THz pulses based on shift currents in type-II-aligned epitaxial semiconductor heterostructures. The measured THz waveforms exhibit only 0.45 optical cycles at their centre frequency within the full width at half maximum of the intensity envelope, peak fields above 1.1 kV cm−1 and spectral components up […]
Thin quantum wires work better with less insulating coatings
Phys.org May 4, 2022 Thin semiconducting wires, referred to as quantum wires, are often coated in insulating materials. Previous studies have explored how the mismatch between the insulating properties of both materials can influence their performance. Researchers in Vietnam have shown that thinner wires with less insulating coatings can improve the mobility of the electrons they carry. Previous models have presented conflicting conclusions about the ability of electrons to move through the wire, depending on whether coatings are more or less insulating than the semiconductor. The researchers considered the case where electrons are allowed to cross the outer boundary of […]
Two teams use neutral atoms to create quantum circuits
Phys.org April 22, 2022 Gate-model quantum computers promise to solve currently intractable computational problems if they can be operated at scale with long coherence times and high-fidelity logic. Neutral-atom hyperfine qubits provide inherent scalability owing to their identical characteristics, long coherence times and ability to be trapped in dense, multidimensional arrays. Combined with the strong entangling interactions provided by Rydberg states all the necessary characteristics for quantum computation are available. An international team of researchers (USA – University of Central Florida, Harvard University, University of Wisconsin-Madison, industry, MIT, UK, Austria,) demonstrated several quantum algorithms on a programmable gate-model neutral-atom quantum […]
Hybrid quantum bit based on topological insulators
Science Daily April 14, 2022 Topological qubits are considered to be particularly robust and largely immune to external sources of decoherence and appear to enable fast switching times comparable to those achieved by the conventional superconducting qubits used in current quantum processors. However, it is not yet clear whether we will ever succeed in producing topological qubits as a suitable material basis is still lacking to experimentally generate the special quasiparticles required for this without any doubt. An international team of researchers (Germany, UK, Denmark, the Netherlands) implemented superconducting transmon qubits with (Bi0.06Sb0.94)2Te3 topological insulator. According to the team microwave […]
Tailored single photons: Optical control of photons as the key to new technologies
Nanowerk April 6, 2022 Several different approaches to realize solid-state quantum emitters with high performance have been pursued and different concepts for energy tuning have been established. However, the properties of the emitted photons are always defined by the individual quantum emitter and can therefore not be controlled with full flexibility. An international team of researchers (Germany, USA – University of Arizona) has developed an all-optical nonlinear method to tailor and control the single photon emission. They demonstrated a laser-controlled down-conversion process from an excited state of a semiconductor quantum three-level system. Based on this concept, they realized energy tuning […]