Showing papers by "Vladimir Eltsov published in 2021"
TL;DR: In this paper, two adjacent quantum time crystals implemented by two magnon condensates in the superfluid B-phase of helium-3 are observed to coherently exchange magnons as a manifestation of the AC Josephson effect.
Abstract: Quantum time crystals are systems characterized by spontaneously emerging periodic order in the time domain1. While originally a phase of broken time translation symmetry was a mere speculation2, a wide range of time crystals has been reported3–5. However, the dynamics and interactions between such systems have not been investigated experimentally. Here we study two adjacent quantum time crystals realized by two magnon condensates in superfluid 3He-B. We observe an exchange of magnons between the time crystals leading to opposite-phase oscillations in their populations—a signature of the AC Josephson effect6—while the defining periodic motion remains phase coherent throughout the experiment. Our results demonstrate that time crystals obey the general dynamics of quantum mechanics and offer a basis to further investigate the fundamental properties of these phases, opening pathways for possible applications in developing fields, such as quantum information processing. Two adjacent quantum time crystals implemented by two magnon condensates in the superfluid B-phase of helium-3 are observed to coherently exchange magnons as a manifestation of the AC Josephson effect, offering insights on the dynamics and interactions between these phases of matter.
43 citations
TL;DR: In this article, the authors used the OtaNano Low Temperature Laboratory infrastructure of Aalto University, which is part of the European Microkelvin Platform (European Union’s Horizon 2020 Grant No. 824109).
Abstract: | openaire: EC/H2020/694248/EU//TOPVAC Funding Information: We thank V. V. Dmitriev for providing the NAFEN sample. This Letter has been supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant Agreement No. 694248) and by Academy of Finland Project No. 332964. S. A. acknowledges support from the Jenny and Antti Wihuri Foundation via the Council of Finnish Foundations, and T. K. acknowledges support from the Finnish Cultural Foundation. This research made use of the OtaNano Low Temperature Laboratory infrastructure of Aalto University, which is part of the European Microkelvin Platform (European Union’s Horizon 2020 Grant No. 824109). Publisher Copyright: © 2021 American Physical Society.
9 citations
Posted Content•
TL;DR: In this paper, the intrinsic damping and the frequency shift in magnetomotively driven aluminum nanoelectromechanical resonators of various sizes at millikelvin temperatures were measured.
Abstract: Tunneling two level systems affect damping, noise and decoherence in a wide range of devices, including nanoelectromechanical resonators, optomechanical systems, and qubits. Theoretically this interaction is usually described within the tunneling state model. The dimensions of such devices are often small compared to the relevant phonon wavelengths at low temperatures, and extensions of the theoretical description to reduced dimensions have been proposed, but lack conclusive experimental verification. We have measured the intrinsic damping and the frequency shift in magnetomotively driven aluminum nanoelectromechanical resonators of various sizes at millikelvin temperatures. We find good agreement of the experimental results with a model where the tunneling two level systems couple to flexural phonons that are restricted to one or two dimensions by geometry of the device. This model can thus be used as an aid when optimizing the geometrical parameters of devices affected by tunneling two level systems.
4 citations
TL;DR: A magnon Bose-Einstein condensate in superfluid $3$He-B is a fine instrument for studying the surrounding macroscopic quantum system at zero temperature and is subject to a few distinct forms of decay into other collective excitations, owing to momentum and energy conservation in a quantum vacuum as mentioned in this paper.
Abstract: A magnon Bose-Einstein condensate in superfluid $^3$He is a fine instrument for studying the surrounding macroscopic quantum system At zero temperature, the BEC is subject to a few, distinct forms of decay into other collective excitations, owing to momentum and energy conservation in a quantum vacuum We study the vortex-Higgs mechanism: the vortices relax the requirement for momentum conservation, allowing the optical magnons of the BEC to transform into light Higgs quasiparticles This observation expands the spectrum of possible interactions between magnetic quasiparticles in $^3$He-B, opens pathways for hunting down elusive phenomena such as the Kelvin wave cascade or bound Majorana fermions, and lays groundwork for building magnon-based quantum devices