New publication just dropped - "Approximate Hofstadter- and Kapit-Mueller-like parent Hamiltonians for Laughlin states on fractals" by me, Michael Iversen and Anne Nielsen, in Physical Review A

https://journals.aps.org/pra/abstract/10.1103/PhysRevA.107.063315
preprint (with a bit older figures with e.g. different color schemes, but the meaning is the same): https://arxiv.org/abs/2301.09971

(and yes, there are over 520 files in the arxiv submission, because it automatically unpacked the zip file with supplementary material)

#physics #quantum #science #CondensedMatter #condmat

New publication: "Cathodoluminescence microscopy for interpreting the fabric and heating process of ancient pottery: Preliminary study on the technological features of pottery from the Kur River basin" #AnalyticalChemistry #Physics #CondensedMatter #Archaeology #CulturalHeritage https://doi.org/10.1111/arcm.12718

Are you an #experimental #physicist? Are you a #postdoc looking to take the next step and to become a #professor? Are you working in #quantum or #condensedmatter? Keep your eyes peeled! More openings at
@UMBC
coming soon!

New publication: "Historical stained-glass window laser preservation: The heat accumulation challenge" #AnalyticalChemistry #Physics #CondensedMatter #Archaeology #CulturalHeritage https://doi.org/10.1016/j.bsecv.2021.12.003

Gravity is much weaker than electromagnetism but still essential to consider in condensed matter physics; but why?🤔

Learn about Luttinger's argument and discuss the gravitational bulk-boundary correspondence online at enabla.com/pub/1115/about 📜🎥

Revise the conformal and gravitational anomalies and explore the interplay between gravity and electromagnetism in the quantum Hall effect⚡️

All Enabla lectures are #free and #OpenAccess. If you like what we're doing, please support us by reposting, following this account, leaving some comments under this post & asking questions on #Enabla. Any of these actions help us a lot; thank you!🙏

#QFT #QuantumFieldTheory #Gravity #CondensedMatter #Quantum #Physics #PhD

🤔Did you know global anomalies in topological superconductors show a different topological invariant from the Altland-Zirnbauer classification? Find out why at https://enabla.com/pub/1111/about 📜🎥 and discuss our new #QFT in #CondensedMatter lecture with its authors🤩

Abstract: In this class, we finish the discussion about global anomalies, discussing global anomalies in topological superconductors. Interestingly, the studies of global anomalies in these materials show a different topological invariant from the Altland-Zirnbauer classification. To understand why, we consider the effect of interactions in topological superconductors, showing that the presence of interactions that respect the symmetry can change the topological class, but this is encoded correctly in the anomalies. Further, we discuss the change of the partition functions when using different frames to describe a Chern-Simons term, what gives rise to the framing anomaly.

All Enabla lectures are #free & #OpenAccess. Please support us by sharing this post, following our account & asking questions on Enabla. Thank you!🙏

#QuantumFieldTheory #Superconductors #Topology #TopologicalSuperconductors #TopologicalMaterials #Physics #Science #Lecture #OpenScience #OpenEducation

#PhysicsFactlet
(Made for a student) For the single frequency oscillation of an infinite chain of identical masses connected by identical springs, the relative phase of oscillation of adjacent masses will depend non-linearly with frequency, resulting in travelling or stationary waves.
For the "diatomic chain", where two different masses alternate, the dependence of relative phase with frequency has two branches (separated by a gap of not allowed frequencies).
#Physics #CondensedMatter #Visualization

Wow!! What a breathe of fresh air this paper is in the midst of suffocating levels of "AI solves everything" hype cycle.

https://arxiv.org/abs/2303.10798

They have found at long last, a single tile, an "einstein", which they call a "hat"/polykite that tiles the entire plane aperiodically.

Previously the best known aperiodic tiling of the plane required at the least two different tiles, the most famous ones being the Penrose tiles, and those that adorn Alhambra.

It is all the more wonderful that the first two authors don't have any academic/research affiliations. They write somewhere in the paper, how it all started, so wonderful:

"One of the authors (Smith) began investigating the hat polykite as part of his open-ended visual exploration of shapes and their tiling properties. Working largely by hand, with the
assistance of Scherphuis’s PolyForm Puzzle Solver software (www.jaapsch.net/puzzles/
polysolver.htm), he could find no obvious barriers to the construction of large patches, and yet no clear cluster of tiles that filled the plane periodically."

Why is the study of tilings such a big deal? Well, it hints at and tries to formalize various physics concepts that are of immense interest to many of us (and dare I say, even neuroscientists): quasi crystals!, possible new states of matter, emergent structures from simple units, how symmetries and asymmetries arise, stability of heterogenous media, soft matter physics, order without periodicity, criticality etc., etc.,

On quasi-crystals and their search, applications, uses etc., I recommend the wonderful Paul Steinhardt's book: "The Second Kind of Impossible: The Extraordinary Quest for a New Form of Matter"

#Physics #Maths #Combinatorics #AperiodicTiling #PenroseTiles #Einstein #Emergence #condensedmatter

We thank Prof Elliott Lieb for taking a long journey from @princeton Princeton
University and giving us an insight into his research work. 🔎 He is a living example of that the age is only a number and you can still accomplish a lot at the age of 91. 🎉
Watch his lecture on YouTube 🔜 www.youtube.com/@ESIVienna

#MathematicalPhysics #Bosegas #condensedmatter #statisticalmechanics #statmech #functionalanalysis

@univienna

https://phys.org/news/2023-03-viable-superconducting-material-temperature-pressure.html
"Viable superconducting material created at low temperature and low pressure"
"In a historic achievement, University of Rochester researchers have created a superconducting material at both a temperature and pressure low enough for practical applications."
#physics #superconductivity #condensedMatter

Our #OpenAccess #QFT #Anomalies in #CondensedMatter #Physics course already includes five lectures and counting🔥 Hans & Rodrigo from #StockholmUniversity & #UppsalaUniversity are doing fantastic work posting videos & lecture notes, and they are waiting for your curious questions to help you better grasp the materials at https://enabla.com/set/153🤓

#QuantumMechanics #QuantumFieldTheory #ConformalFieldTheory #Topology #Symmetry #SymmetryBreaking

As you may have guessed from yesterday's posts, #Enabla is now publishing lectures from #PhD schools, particularly from the #NORDITA #WinterSchool on the #Dynamics of Open #Classical & #Quantum #CondensedMatter Systems

All lectures are available in #OpenAccess at https://enabla.com/set/145; watch the videos, read the notes, and start #ContextDiscussions; lecturers are waiting for your questions!

What are the context discussions? Follow us now not to miss the posts on Enabla #OpenScience features🔥

Like its also-honeycomb-shaped cousin, #graphene, 2D silicon carbide is predicted to have intriguing properties. Researchers in Sweden have now figured out how to make the material.

https://physics.aps.org/articles/v16/s17

#physicsmagazine #sciencemastodon #physicsnews #sciencejournalism #sciencenews #physics #academicmastodon #Siliconcarbide #honeycomb #condensedmatter #materials #materialscience

David Tong's Physics lecture notes are a fantastic resource. They are extremely up to date, well written, freely available, and cover a large range of modern physics from 1st year undergraduate to graduate courses.

I'm posting this as I was shocked to find that my current 4th Year Physics project student's at Imperial hadn't heard about them!

http://www.damtp.cam.ac.uk/user/tong/teaching.html

#Physics #CondensedMatter #QFT #StatMech

#SoftMatter have just published the results of a project that Renato Assante, Davide Marenduzzo, Alexander Morozov, and I recently worked on together! What did we do and what’s new? Briefly…

#Microswimmer suspensions behave in a similar way to fluids containing kinesin and microtubules. Both systems can be described by the same system of three coupled nonlinear #PDEs.

A #LinearStabilityAnalysis of these equations suggests that variations in concentration across the system don’t significantly affect emergent #phaseBehaviour. How then can we explain #experiments that show visible inhomogeneities in #microtubule–#kinesin mixtures, for instance?

With increasing activity, we move away from the quiescent regime, past the onset of #SpontaneousFlow, and deeper into the active phase, where #nonlinearities become more important. What role do concentration inhomogeneities play here?

We investigated these questions, taking advantage of the #openSource #Dedalus #spectral framework to simulate the full nonlinear time evolution. This led us to predict a #novel regime of #spontaneous #microphaseSeparation into active (nematically ordered) and passive domains.

Active flow arrests macrophase separation in this regime, counteracting domain coarsening due to thermodynamic coupling between active matter concentration and #nematic order. As a result, domains reach a characteristic size that decreases with increasing activity.

This regime is one part of the #PhaseDiagram we mapped out. Along with our other findings, you can read all about it here!

low #ReynoldsNumber #turbulence #ActiveTurbulence #CahnHilliard #ActiveMatter #NavierStokes #BerisEdwards #CondensedMatter #PhaseTransitions #TheoreticalPhysics #BioPhysics #StatisticalPhysics #FluidDynamics #ComputationalPhysics #Simulation #FieldTheory #paperthread #NewPaper #science #research #ActiveGel #activeNematic #analytic #cytoskeleton #hydrodynamics #MPI #theory

#SoftMatter have just published the results of a project that Renato Assante, Davide Marenduzzo, Alexander Morozov, and I recently worked on together! What did we do and what’s new? Briefly…

The #hydrodynamic behaviour of inhomogeneous #activeNematic gels (such as extensile bundles of #cytoskeletal filaments or suspensions of low #ReynoldsNumber swimmers) can be described by the time evolution of three coupled #PDEs.

Standard #ActiveGel #theory concludes, from a #LinearStabilityAnalysis of these equations, that fluctuations in concentration don’t significantly affect emergent #phaseBehaviour. However, this leaves #experimental #observations of visible inhomogeneities in #microtubule–#kinesin mixtures unexplained. As we move away from the passive (quiescent) regime, past the onset of #SpontaneousFlow, and deeper into the active phase, #nonlinearities become more important. What role do concentration inhomogeneities play here?

Alongside #analytic techniques, we used an in-house #MPI-parallel code developed within the #Dedalus #spectral framework to investigate. We predict a #novel regime of #spontaneous #microphaseSeparation into active (nematically ordered) and passive domains. In this regime, active flow arrests macrophase separation, which is itself driven by the thermodynamic coupling between active matter concentration and #nematic order. As a result, domains do not #coarsen past a typical size, which decreases with increasing activity. This regime is one part of the #PhaseDiagram we mapped out.

Along with our other findings, you can read all about it here!

#CahnHilliard #ActiveMatter #NavierStokes #BerisEdwards #CondensedMatter #PhaseTransitions #TheoreticalPhysics #BioPhysics #StatisticalPhysics #FluidDynamics #ComputationalPhysics #Simulation #FieldTheory #paperthread #NewPaper #science #research

A heavily updated preprint on validating and extending the Feynman variational polaron solution + FHIP mobility theory to real materials.

We find the 60 year old FHIP theory agrees almost perfectly with recent Diagrammatic QMC calculations, and that extending the theory to multiple phonon modes starts to show rich structure in the frequency response of mobility.

With Brad Martin (https://twitter.com/Neutrino155)

https://arxiv.org/abs/2203.16472

#CondensedMatter #CompChem #JuliaLang #Polarons

So, there are still no known cospectral fullerene graphs?
I've found only mentions of fullerenes with cospectral duals. These model closo-borane anions, but aren't they too exotic?
Anyway, I'm looking for chemically-motivated regular graphs that have cospectral adjacency matrices to test graph invariants arising from variational JAGP-like wavefunctions.

#GraphTheory #ChemicalGraphTheory #Quantum #CondensedMatter #Chemistry #Physics

Evaluation of thermal conductivity
@physics #condensedmatter

https://pubs.acs.org/doi/full/10.1021/acs.jpca.2c06286

[New server, new #introduction, this time with hashtags!]

Hello! I'm a #TheoreticalPhysicist working in #Quantum #CondensedMatter #Physics, currently a #MarieSklodowskaCurie Fellow at FU Berlin. I'm interested in how #disorder affects quantum systems, and how we can use it to stabilise exotic phases of matter.

More info: http://www.steventhomson.co.uk

I also host the @insidequantum #podcast where I talk to the people behind the latest developments in #QuantumTechnology. Please check it out!