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UK Quantum Fluids
United Kingdom
Приєднався 26 січ 2021
UK Quantum Fluids network webinar series uk-quantum-fluids-network.github.io/webinars/
Rotating dipolar gases: supersolids, vortices, and glitches
Speaker: Elena Poli (Institut für Experimentalphysik, Universität Innsbruck)
Since the first observation of a Bose-Einstein condensate (BEC) made from strongly magnetic atoms, these systems have proven to be a rich source of new and fascinating phenomena arising from the long-range and anisotropic dipole-dipole interaction. Recently, these dipolar quantum gases have proven to be a versatile platform in order to observe the long-sought after supersolid phase-a state that simultaneously manifests a crystalline order and superfluid properties. Here, I will present the latest results from our research on ultracold dipolar quantum gas in Innsbruck, with a particular focus on the combined theoretical and experimental effort to understand the rotational properties of these systems in different phases. The presence of quantized vortices-topological defects of the wavefunction characterized by a 2π phase winding-consists of one of the most distinctive manifestations of their superfluid nature. I will report on the theoretical study and experimental observation of quantized vortices in a strongly magnetic gas of dysprosium atoms in both the unmodulated BEC and supersolid phases [1,2]. Finally, I will show an application of rotating dipolar supersolids, i.e. the possibility to simulate “glitches”, instantaneous jumps of the rotation frequency occurring due to the internal vortex dynamics, akin to observations in neutron stars [3].
[1] L. Klaus, T. Bland et al., Nature Physics 18, 1453-1458 (2022).
[2] E. Casotti, E. Poli et al., arXiv:2403.18510 (2024).
[3] E. Poli et al., Phys. Rev. Lett. 131, 223401 (2023).
Since the first observation of a Bose-Einstein condensate (BEC) made from strongly magnetic atoms, these systems have proven to be a rich source of new and fascinating phenomena arising from the long-range and anisotropic dipole-dipole interaction. Recently, these dipolar quantum gases have proven to be a versatile platform in order to observe the long-sought after supersolid phase-a state that simultaneously manifests a crystalline order and superfluid properties. Here, I will present the latest results from our research on ultracold dipolar quantum gas in Innsbruck, with a particular focus on the combined theoretical and experimental effort to understand the rotational properties of these systems in different phases. The presence of quantized vortices-topological defects of the wavefunction characterized by a 2π phase winding-consists of one of the most distinctive manifestations of their superfluid nature. I will report on the theoretical study and experimental observation of quantized vortices in a strongly magnetic gas of dysprosium atoms in both the unmodulated BEC and supersolid phases [1,2]. Finally, I will show an application of rotating dipolar supersolids, i.e. the possibility to simulate “glitches”, instantaneous jumps of the rotation frequency occurring due to the internal vortex dynamics, akin to observations in neutron stars [3].
[1] L. Klaus, T. Bland et al., Nature Physics 18, 1453-1458 (2022).
[2] E. Casotti, E. Poli et al., arXiv:2403.18510 (2024).
[3] E. Poli et al., Phys. Rev. Lett. 131, 223401 (2023).
Переглядів: 301
Відео
Quantum Hall physics in a quantum Foucault pendulum'
Переглядів 1,4 тис.6 місяців тому
Speaker: Richard Fletcher (MIT, USA) When charged particles are placed in a magnetic field, the single-particle energy states form discrete, highly-degenerate Landau levels. Since all states within a Landau level have the same energy, the behaviour of the system is completely determined by the interparticle interactions and strongly-correlated behaviour such as the fractional quantum Hall effec...
False vacuum decay via bubble formation in ferromagnetic superfluids
Переглядів 2816 місяців тому
Speaker: Riccardo Cominotti (Pitaevskii BEC Center, CNR-INO, Università di Trento, Italy). Abstract: A classical system can have multiple equilibrium states at different energies; the absolute ground state is a stable configuration, while the other local energy minima are metastable. In a quantum field theory, quantum fluctuations can trigger the macroscopic tunneling of the field from a metast...
Flow visualization in superfluid helium-4 (with particles)
Переглядів 1697 місяців тому
The contribution of this experimental technique to our understanding of turbulent flows of superfluid helium-4 is reviewed and special emphasis is given to recent results obtained in Prague. Specifically, it is shown that flow visualization data can be employed to estimate (i) the mean distance between quantized vortices, especially in conditions that cannot be accessed by the standard second s...
Vortex dynamics in dipolar superfluids
Переглядів 6207 місяців тому
The static and dynamic properties of vortices in dipolar Bose-Einstein condensates (dBECs) can be considerably modified relative to their nondipolar counterparts by the anisotropic and long-ranged nature of the dipole-dipole interaction (DDI). In the context of a uniform, three-dimensional dBEC, I will present recent results on the structure of single vortex lines and the dynamics of pairs of v...
Monopoles, Alice rings and topological interfaces in spinor Bose-Einstein condensates
Переглядів 6377 місяців тому
Giuseppe Baio (University of East Anglia) gives a webinar on 'Monopoles, Alice rings and topological interfaces in spinor Bose-Einstein condensates'. Recent experimental advancements in ultracold atoms are leading to the controlled creation of complex topological excitations in spinor Bose-Einstein condensates (BECs) [1]. In this webinar, I will address defects and their dynamics in a spin-2 BE...
Superfluid vortex crystals and their quantum melting
Переглядів 5108 місяців тому
Sergej Moroz (Karlstad University) gives a webinar on ‘Superfluid vortex crystals and their quantum melting’. I will present our investigations of a low-energy effective field theory of a two-dimensional superfluid vortex crystal which reduces to a scalar Lifshitz theory in the linearized approximation. General symmetry considerations allow us to determine non-linear terms that fix a decay rate...
Flying in a superfluid: starting flow past an airfoil
Переглядів 4969 місяців тому
Seth Musser (MIT) presenting ‘Flying in a superfluid: starting flow past an airfoil’ journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.154502 In typical fluids like air or water viscosity plays a crucial role in flight. It allows for the development of a boundary layer that separates from an airfoil when it is accelerated from rest; this separation forms the starting vortex that allows for ...
Quantum turbulence: Phenomenological experimentalist’s view, and where do we go next?
Переглядів 1889 місяців тому
Ladislav Skrbek (Charles University) gives a webinar on Quantum turbulence in helium superfluids: Phenomenological experimentalist’s view, and where do we go next?. The talk is an overview of selected topics of quantum turbulence (QT) [1] - the stochastic motion of quantum fluids He II and 3He-B, recently described in detail in Ref. [1]. We focus on unified phenomenological description of 3D QT...
Catalyzation of supersolidity in Dipolar Binary Mixtures
Переглядів 18411 місяців тому
Luis Aldemar Peña Ardila (University of Camerino) gives a webinar on Catalyzation of supersolidity in Dipolar Binary Mixtures. Breakthrough experiments have newly explored the fascinating physics of dipolar quantum droplets and supersolids. The recent realization of dipolar mixtures opens further intriguing possibilities. We show that under rather general conditions, the presence of a second co...
Quantum-to-Classical Vortex Flow: Quantum Field Theory Dynamics in Rotating Curved Spacetimes
Переглядів 1,5 тис.11 місяців тому
Exploring the Quantum-to-Classical Vortex Flow: Quantum Field Theory Dynamics in Rotating Curved Spacetimes Patrik Svancara (University of Nottingham, UK, QSimFP consortium qsimfp.org/ ). See arxiv.org/abs/2308.10773 for more details Gravity simulators are laboratory systems where small excitations like sound or surface waves behave as fields propagating on a curved spacetime geometry. The anal...
Superflow in ultracold atomic rings: from persistent currents to Kelvin-Helmholtz instability
Переглядів 195Рік тому
Giulia Del Pace (University of Florence and LENS, Italy) talks about “Superflow in ultracold atomic rings: from persistent currents to Kelvin-Helmholtz instability”. The emergence of persistent currents in rings is one of the most striking manifestations of a quantum system coherence. The periodic boundary of such a geometry constrains the wavefunction phase to wind in a loop of an integer mult...
Applying superfluid ⁴He to the search for low-mass dark matter
Переглядів 241Рік тому
Scott Hertel (University of Massachusetts, USA) talks about “Applying superfluid 4He to the search for low-mass dark matter” at 4pm UK time. We report on recent R&D work towards “HeRALD”, a search for low-mass dark matter using a superfluid 4He target. Dark matter scatters within the 4He target may produce atomic recoils, detectable via roton quantum evaporation at the liquid surface. Recent wo...
Exotic many-body states in dipolar quantum Bose gases of magnetic atoms
Переглядів 358Рік тому
Lauriane Chomaz (University of Heidelberg) talks about “Exotic many-body states in dipolar quantum Bose gases of magnetic atoms”. Ultracold quantum gases provide a pristine platform to study few-body and many-body quantum phenomena with an exquisite degree of control. The achievement of quantum degeneracy in gases of atoms with large magnetic dipole moments in their electronic ground states has...
Superfluid neutron stars and pulsar glitches
Переглядів 613Рік тому
Nils Andersson (University of Southampton, UK) talks about "Superfluid neutron stars and pulsar glitches". In this talk I will discuss the dynamical role of superfluidity in neutron stars, motivating why we expect these objects to be superfluid in the first place and outlining how superfluidity impacts on the hydrodynamics of the system. In particular, I will compare and contrast neutron-star s...
Direct visualization of the quantum vortex density law in rotating 4He
Переглядів 418Рік тому
Direct visualization of the quantum vortex density law in rotating 4He
Emergent isotropy of a wave-turbulent cascade in the Gross-Pitaevskii model
Переглядів 202Рік тому
Emergent isotropy of a wave-turbulent cascade in the Gross-Pitaevskii model
Universal dynamics of a turbulent superfluid Bose gas
Переглядів 207Рік тому
Universal dynamics of a turbulent superfluid Bose gas
Dissipative time crystals in an atom-cavity platform
Переглядів 387Рік тому
Dissipative time crystals in an atom-cavity platform
Experiments on Inhomogeneous Quantum Turbulence in Superfluid ⁴He
Переглядів 5932 роки тому
Experiments on Inhomogeneous Quantum Turbulence in Superfluid ⁴He
Physics of superfluid ⁴He in two-dimensional confinement
Переглядів 2912 роки тому
Physics of superfluid ⁴He in two-dimensional confinement
Programmable networks of exciton-polariton condensates
Переглядів 1,7 тис.2 роки тому
Programmable networks of exciton-polariton condensates
Rotating quantum wave turbulence and onset of the Kelvin wave cascade.
Переглядів 1782 роки тому
Rotating quantum wave turbulence and onset of the Kelvin wave cascade.
Wave turbulence in homogeneous Bose gases
Переглядів 1892 роки тому
Wave turbulence in homogeneous Bose gases
Amplification of waves from rotating media
Переглядів 1862 роки тому
Amplification of waves from rotating media
Origin and evolution of the multiply-quantised vortex instability
Переглядів 1582 роки тому
Origin and evolution of the multiply-quantised vortex instability
The sound-ring radiation of expanding vortex clusters
Переглядів 2092 роки тому
The sound-ring radiation of expanding vortex clusters
Fermionic superfluidity: from single vortex dynamics to quantum turbulence
Переглядів 4972 роки тому
Fermionic superfluidity: from single vortex dynamics to quantum turbulence
Awesome topic, terrible presentation
How did they stopped it in lab
Source, Sabine Hossenfelder (first experiment evidence for process that might create the Universe)
your understanding of light is incorrect.
Amazing breakdown and presentation! Loved having the opportunity to listen to this!
Hi, I'm a lay person, like to know if that experiment prove that the Big bang it's a fase transicion?
No, the experiment likely does not have such implications as I understand it.
I, sorry if I take your time, I'm very confused cause I see many videos about false vacuum, and Sabine Hossenfelder mencion an experiment that I believe is what you talk about, whit cold atoms, that his a process that can create the universe or ended too.....
I'm spinning around Move out of my way I know you're feelin' me 'cuz you like it like this I'm breakin' it down I'm not the same I know you're feelin' me 'cuz you like it like this
Excellent presentation. Well explained too. You're looking at the future inventions, and applications, in Your work, especially with that dual gravity model. Suggest You keep thinking outside the box and see what's there. It's there!
How many pairs of Poles does a bar magnet have? And is rotation an intrinsic property of a vortex? To call a smaller scale of it as "irrotational" is downright deranged.... sure they spin really fast and it's extremely difficult to measure the rpm using modern tech but please... abstraction is only justified when you aren't omitting foundational phenomena like Spin and Rotation.
If "they" proved Planck's Quanta interpretation by demonstrating that Angular Momentum is indeed quantised then why do also say that it has Spin with no classical analogue? Kinda weird that the mainstream phenomenology is that of the planetary model rather than helmholtz or taits models...
At the end the edge modes perhaps to do with chiral chern Simons theory as it relevant in other cases
'Promo sm' 💯
Nice
This is awesome
Thanks for the wonderfully relevant suggestions youtube haha this all sure sounds interesting though
Spoiler: It's neutrinos after all, ejected from black holes (and possibly heavy enough neutron stars to hold onto relativistic neutrinos) with local, extreme densities resulting from millions and billions of years of accumulation of them in those places. The streams of these comparatively cold, electromagnetism ignoring, friction-less and hence obviously super-fluid neutrinos that are the only known kind of particle (with their 3 types, tauon neutrino, muon neutrino, electron neutrino) besides photons that are (due to their low mass and relativistic speeds) capable to be spread across inter-galactic space while at the same time being captured by massive black holes where they transfer their impulse from 1 galaxy to a nearby one develop into differently compact, expanded swarms, though they also act as dark energy by obtaining a gravitational-assist-like swing-by motion since the gravitational lensing effect doesn't only apply to light but such neutrinos in their extremely high abundances throughout the cosmos, too, by which they also pull onto galaxies in direction away from the galaxy they came from, explaining the dark energy phenomenon, too. It really wasn't all that complicated (e.g. compared to figuring out glitches in video games) for if only physicists hadn't been so fixated on the logically and observationally contradictory existence of event horizons (that neither Einstein nor Hawking believed in) to imply nonsensical causal 1-way streets at the non-existent boundary towards black holes. And so instead of focusing on the invention of new particles to explain dynamical possibilities that are explainable without them for if one had been more thorough, exhaustive in the analysis of possibilities with the particle set that was already known to exist, before ruling them out, this could and should have been figured out a lot sooner. Good luck on further research during which you then might find out that such by black holes ejected neutrino swarms can in some cases be in a labile to each other bound state that can be disturbed by close encounters of massive objects pulling on 1 side of them stronger than the other, which can disrupt such neutrino swarms, leading to the dissolving of them, explaining suddenly disappearing "black holes", and that those impossibly huge and particle density lacking super puff gas planets are just neutrino swarms that gather interstellar gas and other material as they move through space (which is also how they can be slowed down especially near stars with proto-planetary material discs to form binary systems of the loosest to each other bound type with orbital periods in the millions of years), and that these neutrino swarms, since they are invisible and hence possible to be confused with a black look of them that could be interpreted as black hole, can mimic black holes with for black holes impossibly low total masses and dormant behaviors nearby stars in binary star systems. The situation at Tabby's star should be explainable this way, too, and likely the planet 9 mystery as well (and more).
hello, how to get on the e-mail list for this webinar series?
Please contact the series organisers by email. Details can be found on the series website uk-quantum-fluids-network.github.io/webinars/
Am i the only one who thinks the energy cascade is linked to extra dimensions of string theory? So that they are virtual.
Fabulous
Hi, Can anyone explain why there is a Bohr radius term in the interaction ?
Dear Sushil Apologies for the late reply and thanks for your comment. You are right that this is a typo (I probably mixed up two equations at some point). Regarding the proper expression, I can recommend [M.S. Skolnick, T.A Fisher, D.M. Whittaker, Semicond. Sci. Technol. 13, 645 (1998)], see equations 6-8. :) Best regards, Helgi
And when more people watch the video, the amount of "views" don't change. What it means, after all?
It is the UA-cam algorithm that defines what a "view" is.
Somebody is deleating "likes". A one hour ago there were 7 likes, now only four.
As far as I am aware, it is only possible to delete your own "likes", not anyone else's. How UA-cam may be counting separate viewers, I don't know.