Phys.org April 19, 2024 The polarization of single photons are used as addressable degrees of freedom for turning the interference of nonclassical states of light into practical applications. However, the scale-up for the processing of a large number of photons of these architectures is very resource-demanding due to the rapidly increasing number of components, such as optical elements, photon sources, and detectors. An international team of researchers (Austria, Italy, Belgium) demonstrated a resource-efficient architecture for multiphoton processing based on time-bin encoding in a single spatial mode. They used an efficient quantum dot single-photon source and a fast programmable time-bin interferometer […]
Tag Archives: Quantum computing
New research area promotes both quantum computing and cognitive science
Phys.org March 26, 2024 Quantum biology applies quantum mechanics to biological systems at the molecular scale. Molecular quantum computing explores the degrees of freedom of molecules that can be used to produce quantum coherence. Cognitive science focuses on understanding how learning processes are realized, particularly within the human brain. An international team of researchers (US, USA – New Jersey Institute of Technology, Morgan State University) reviewed progress in quantum biology, molecular quantum computing, and quantum theory in cognitive science. Based on their analysis and review, they highlighted that molecular quantum computing could be an important bridging research area between quantum […]
New ion cooling technique could simplify quantum computing devices
Phys.org February 6, 2024 In current QCCD implementations, imperfect ion transport and anomalous heating can excite ion motion during a calculation. To counteract this, intermediate cooling is necessary to maintain high-fidelity gate performance. Cooling the computational ions sympathetically with ions of another species creates a significant runtime bottleneck. Researchers at the Georgia Institute of Technology demonstrated exchange cooling which does not require trapping two different atomic species. They introduced a bank of “coolant” ions which were repeatedly laser cooled. A computational ion could be cooled by transporting a coolant ion into its proximity. Experimentally they tested this concept and executed […]
Microsoft claims to have achieved first milestone in creating a reliable and practical quantum computer
Phys.org. June 24, 2023 Researchers at Microsoft (USA) engineered a new way to represent a logical qubit with hardware stability. They reported that the device could induce a phase of matter characterized by Majorana zero modes, such devices have demonstrated low enough disorder to pass the topological gap protocol, proving the technology is viable. They stated that it has created a new measure to gauge the performance of a quantum supercomputer: reliable quantum operations per second (rope), a figure that describes how many reliable operations a computer can execute in a single second. They suggest that for a machine to […]
The first lab-created ‘quantum abacus’
Phys.org February 2, 2023 An international team of researchers (UK, Italy) has reported the experimental realization of the prime number quantum potential VN(x), defined as the potential entering the single-particle Schrödinger Hamiltonian with eigenvalues given by the first N prime numbers. Using computer-generated holography, they created light intensity profiles suitable to optically trap ultracold atoms in these potentials for different N values. As a further application, they implemented a potential whose spectrum is given by the lucky numbers, a sequence of integers generated by a different sieve than the familiar Eratosthenes’s sieve used for the primes. According to the researchers their results pave the way […]
New quantum computing architecture could be used to connect large-scale devices
Science Daily January 5, 2023 Quantum information transfer between arbitrary nodes is generally mediated either by photons that propagate between them or by resonantly coupling nearby nodes. The utility is determined by the type of emitter, propagation channel and receiver. Conventional approaches involving propagating microwave photons have limited fidelity due to photon loss and are often unidirectional, whereas architectures that use direct resonant coupling are bidirectional in principle but can generally accommodate only a few local nodes. Researchers at MIT have demonstrated high-fidelity, on-demand, directional, microwave photon emission by using an artificial molecule comprising two superconducting qubits strongly coupled to […]
Imposter physical particles revealed: A key advance for quantum technology
Phys.org December 16, 2022 Hybrid semiconductor–superconductor devices hold great promise for realizing topological quantum computing with Majorana zero modes. However, multiple claims of Majorana detection, based on either tunnelling or Coulomb blockade (CB) spectroscopy, remain disputed. An international team of researchers (Austria, USA – Princeton University, Spain) devised an experimental protocol that allowed them to perform both types of measurement on the same hybrid island by adjusting its charging energy via tunable junctions to the normal leads. This method reduces ambiguities of Majorana detections by checking the consistency between CB spectroscopy and zero-bias peaks in non-blockaded transport. They observed junction-dependent, […]
Electron pairing in quantum dots as a new approach to qubit research
Phys.org November 25, 2022 Materials with intrinsic p-wave superconductivity, hosting Cooper pairs made of equal-spin electrons, have not been conclusively identified, nor synthesized, despite promising progress. Instead, engineered platforms where s-wave superconductors are brought into contact with magnetic materials have shown convincing signatures of equal-spin pairing. Researchers in the Netherlands have directly measured equal-spin pairing between spin-polarized quantum dots. The pairing is proximity-induced from an s-wave superconductor into a semiconducting nanowire with strong spin–orbit interaction. They demonstrated such pairing by showing that breaking a Cooper pair can result in two electrons with equal spin polarization. Their results demonstrated controllable detection […]
Erbium atoms in silicon: A prime candidate for quantum networks
Phys.org November 7, 2022 A major challenge for a scalable architecture for quantum information processing is based on emitters in nanostructures that are coupled by light. Researchers in Germany demonstrated the integration of erbium atoms with special optical properties into a silicon crystal. Thus, the atoms could be connected by light at a wavelength that is commonly used in telecommunications, making them ideal building blocks for future quantum networks that enable calculations with several quantum computers, as well as the secure exchange of data in a quantum internet. They achieved a narrow inhomogeneous broadening, less than 1 GHz, strong optical […]
From bits to p-bits: One step closer to probabilistic computing
Nanowerk August 29, 2022 To engineer probabilistic computers for more advanced computers researchers in Japan have developed a mathematical description to understand what happens to p-bits which could form the basis of probablistic computing. They utilized superparamagnetic tunnel junctions that have high sensitivity to external perturbations and determined the exponents through several independent measurements. They experimentally clarified the ‘switching exponent’ that governs fluctuation under the perturbations caused by magnetic field and spin-transfer torque in magnetic tunnel junctions. This gave them the mathematical foundation to implement magnetic tunnel junctions into the p-bit to sophisticatedly design probabilistic computers. They showed that these […]