Phys. org January 31, 2024 Ultracold polyatomic molecules offer opportunities in cold chemistry, precision measurements and quantum information processing because of their rich internal structure. However, their increased complexity compared with diatomic molecules presents a challenge in using conventional cooling techniques. An international team of researchers (Germany, China) demonstrated an approach to create weakly bound ultracold polyatomic molecules by electroassociation in a degenerate Fermi gas of microwave-dressed polar molecules through a field-linked resonance. They created around weakly bound tetratomic (NaK)2 molecules more than 3,000 times colder than previously realized tetratomic molecules. They observed a maximum tetramer lifetime of 8(2)?ms in […]
Tag Archives: Quantum information processing
Quantum technology reaches unprecedented control over captured light
Phys.org September 27, 2022 An international team of researchers (Sweden, Japan) has developed a technique to overcome to noise and interference in quantum systems. Their technique could create any of the previously demonstrated states and the cubic phase state. They used a sequence of interleaved selective number-dependent arbitrary phase (SNAP) gates and displacements. The state preparation was optimized in two steps – first they used a gradient-descent algorithm to optimize the parameters of the SNAP and displacement gates; then optimized the envelope of the pulses implementing the SNAP gates. The results showed that this way of creating highly nonclassical states […]
Cooling radio waves to their quantum ground state
Phys.org October 15, 2021 In standard cryogenic systems thermal decoherence prevents access to the quantum regime for photon frequencies below the gigahertz domain. An international team of researchers (the Netherlands, Germany) engineered two superconducting LC circuits coupled by a photon-pressure interaction and demonstrated sideband cooling of a hot radio frequency (RF) circuit using a microwave cavity. Because of a substantially increased coupling strength, they obtained a large single-photon quantum cooperativity and reduced the thermal RF occupancy by 75% with less than one pump photon. For larger pump powers, the coupling rate exceeds the RF thermal decoherence rate by a factor […]
Twistoptics: A new way to control optical nonlinearity
Science Daily March 4, 2021 A hot topic in the field of 2D materials has been exploring how twisting can change the electronic properties of the layered system. van der Waals (vdW) heterostructures feature layers that can be stacked at arbitrary angles, giving complete control over the presence or lack of inversion symmetry at a crystal interface. An international team of researchers (USA – Columbia University, industry, Germany, Japan) demonstrated highly tunable second harmonic generation (SHG) using bulk hexagonal boron nitride crystals and introduced the term twistoptics to describe studies of optical properties in twistable vdW systems. By suppressing residual […]
A two-atom quantum duet
Science Daily November 9, 2018 While a single spin is easily disrupted, a coupled-spin system can resist decoherence by using a subspace of states that is immune to magnetic field fluctuations. An international team of researchers (South Korea, USA – industry) engineered the magnetic interactions between the electron spins of two spin-1/2 atoms to create a “clock transition” and thus enhance their spin coherence. To construct and electrically access the desired spin structures, they used atom manipulation combined with electron spin resonance. They showed that a two-level system composed of a singlet state and a triplet state is insensitive to […]
The quantum technologies roadmap: a European community view
New Journal of Physics August 1, 2018 In 2016 EU created a 150-page QT Roadmap . This article presents an updated summary of the roadmap. Software, protocols, and quantum information theory are essential for an optimal development of QT. Until now, most of the effort has focused on identifying the ultimate limits for quantum information processing. In the next 5–10 years, a parallel effort will be devoted to understanding what can be done with the first generations of small quantum processors, identifying for instance quantum computation protocols whose classical simulation is infeasible or realisation of protocols with unprecedented levels of security. […]
Physicists show that is impossible to mask quantum information in correlations
Phys.org June 21 2018 Classical information encoded in composite quantum states can be completely hidden from the reduced subsystems and may be found only in the correlations. An international team of researchers (Australia, India) has shown that while this may still be true for some restricted sets of nonorthogonal quantum states, it is not possible for arbitrary quantum states. This result suggests that quantum qubit commitment—a stronger version of the quantum bit commitment—is not possible in general. The findings may have potential applications in secret sharing and future quantum communication protocols…read more. TECHNICAL ARTICLE