Using an atomic array originally designed for quantum memory, researchers have demonstrated a magnetometer with unprecedented spatial resolution.
Category: quantum physics – Page 254
Google’s Quantum AI Challenges Long-Standing Physics Theories
Quantum simulators are now addressing complex physics problems, such as the dynamics of 1D quantum magnets and their potential similarities to classical phenomena like snow accumulation. Recent research confirms some aspects of this theory, but also highlights challenges in fully validating the KPZ universality class in quantum systems. Credit: Google LLC
Quantum simulators are advancing quickly and can now tackle issues previously confined to theoretical physics and numerical simulation. Researchers at Google Quantum AI and their collaborators demonstrated this new potential by exploring dynamics in one-dimensional quantum magnets, specifically focusing on chains of spin-1/2 particles.
They investigated a statistical mechanics problem that has been the focus of attention in recent years: Could such a 1D quantum magnet be described by the same equations as snow falling and clumping together? It seems strange that the two systems would be connected, but in 2019, researchers at the University of Ljubljana found striking numerical evidence that led them to conjecture that the spin dynamics in the spin-1⁄2 Heisenberg model are in the Kardar-Parisi-Zhang (KPZ) universality class, based on the scaling of the infinite-temperature spin-spin correlation function.
CMSP series of lectures on “Topology and dynamics of higher-order networks”: lecture 3
ICTP lectures “Topology and dynamics of higher-order networks”
- Network topology: 1 https://youtube.com/watch?v=mbmsv9RS3Pc&t=7562s.
- Network topology:2 https://youtube.com/watch?v=F6m5lPfk5Mc&t=3808s.
-Network geometry.
Topological Dirac equation and Discrete Network Geometry-Metric cohomology Speaker: Ginestra Bianconi (Queen Mary University of London) Higher-order networks [1] capture the many-body interactions present in complex systems and are dramatically changing our understanding of the interplay between topology of and dynamics. In this context, the new field of topological signals is emerging with the potential to significantly transform our understanding of the interplay between the structure and the dynamics in complex interacting systems. This field combines higher-order structures with discrete topology, discrete topology and dynamics and shows the emergence of new dynamical states and collective phenomena. Topological signals are dynamical variables, not only sustained on the nodes but also on edges, or even triangles and higher-order cells of higher-order networks. While traditionally network dynamics is studied by focusing only on dynamical variables associated to the nodes of simple and higher-order networks topological signals greatly enrich our understanding of dynamics in discrete topologies. These topological signals are treated by using algebraic topology operators as the Hodge Laplacian and the discrete Dirac operator. Recently, growing attention has been devoted to the study of topological signals showing that topological signals undergo collective phenomena and that they offer new paradigms to understand on one side how topology shape dynamics and on the other side how dynamics learns the underlying network topology. These concepts and idea have wide applications. Here we cover example of their applications in mathematical physics and dynamical systems. The field is topical at the moment with many new results already established and an already rich bibliography, therefore it is very timely to propose a series of lectures on the topic to introduce new scientists to this emergent field. Here we propose a series of lectures for a broad audience of scientists addressed mostly to physicist and mathematicians, but including also computer scientists and neuroscientists. The course is planned to be introductory, and self-contained starting from minimum set of prerequisites and focus mostly on the mathematical physics aspect of this field. The course will cover 4 lectures and 1 seminar. Ref: [1] Bianconi, G.: Higher-order networks: An introduction to simplicial complexes. Cambridge University Press (2021). [2] Bianconi, G., 2021. The topological Dirac equation of networks and simplicial complexes. Journal of Physics: Complexity, 2, p.035022.[3]Bianconi, G., 2023. The mass of simple and higher-order networks. Journal of Physics A: Mathematical and Theoretical, 57, p.015001.[4] Bianconi, G., 2024. Quantum entropy couples matter with geometry. arXiv preprint arXiv:2404.08556.[5] Millán, A.P., Torres, J.J. and Bianconi, G., 2020. Explosive higher-order Kuramoto dynamics on simplicial complexes. Physical Review Letters, 124(21), p.218301.
New model suggests partner anti-universe could explain accelerated expansion without the need for dark energy
The accelerated expansion of the present universe, believed to be driven by a mysterious dark energy, is one of the greatest puzzles in our understanding of the cosmos. The standard model of cosmology called Lambda-CDM, explains this expansion as a cosmological constant in Einstein’s field equations. However, the cosmological constant itself lacks a complete theoretical understanding, particularly regarding its very small positive value.
Physicists coax molecules into exotic quantum state — ending decades-long quest
The results are “fantastic”, says Yan. They will “really inspire and stimulate the rest of the cold-molecules community”
Exotic phases
Molecular Bose–Einstein condensates could be used in myriad ways. One possibility, says Valtolina, is to create exotic supersolid phases, in which a rigid material flows without resistance. So far this has been achieved only in atomic gases with magnetic interactions — it could now be done in polar molecules, whose interactions are “way stronger”, he says.
Superconducting circuit for qubit control within large-scale quantum computer systems successfully demonstrated
In support of the development of large-scale superconducting quantum computers, researchers with the National Institute of Advanced Industrial Science and Technology (AIST), one of the largest public research organizations in Japan, in collaboration with Yokohama National University, Tohoku University, and NEC Corporation, proposed and successfully demonstrated a superconducting circuit that can control many qubits at low temperature.
Nanoscale Discovery Offers a New, Energy-Efficient Approach to Quantum Computing
A collaborative study by researchers at Lancaster and Radboud universities has pioneered a method to generate and control spin waves at the nanoscale, offering a new, energy-efficient approach to quantum computing.
Researchers at Lancaster University and Radboud University Nijmegen have successfully produced propagating spin waves on the nanoscale, unveiling a new method to modulate and amplify these waves.
Their discovery, published in Nature, could pave the way for the development of dissipation-free quantum information technologies. As the spin waves do not involve electric currents these chips will be free from associated losses of energy.