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#condensedmatter

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Öffentlich
QUINTO project

Atom arrays

Scientists have developed ways of trapping atoms and arranging them in space using laser beams (such as “optical tweezers” and “optical lattices”). What can one do using these tools? One possibility is arranging the atoms in a regular array.

Why people find it interesting? It was found that such systems have properties much different than clouds of atoms randomly flying around. The lattice structure changes how the atoms emit and absorb light. This is because light emitted from different atoms can interfere, and a regular structure of array works like a diffraction grating. This happens especially if the distance between atoms is smaller than one wavelength.

For example, a 1D chain of atoms in a certain state emits light only on its ends. And a 2D array can act as a perfect mirror (for certain wavelength), even though it is only one atom thin.

It was theoretically shown that these effects can be used to boost the efficiency of optical quantum devices such as memories and gates, which may be used in the future for a “quantum internet” and quantum computers.

#Physics #Science #Quantum #QuantumOptics #atoms #CondensedMatter #CondMat

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Öffentlich *
QUINTO project

Hi!
We are conducting a research project on the intersection of quantum optics and condensed matter. We study what happens if an ordered array of atoms absorbs many photons, thus becoming a complex system of many interacting particles. We want to find and exploit analogies between such systems and so-called topological orders, and build a “bridge” between the two fields of physics.
#introduction #Physics #CondensedMatter #CondMat #QuantumOptics #TopologicalOrder #ManyBody #ColdAtoms

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Öffentlich
Florian Marquardt

Going to the spring meeting of the German Physical Society #DPG in #Berlin?

We are organizing a symposium on artificial intelligence in condensed matter. It starts 9:30am Monday in H0104 with an invited talk by Eliska Greplova @eliska ! Maybe see you there...
dpg-verhandlungen.de/year/2024

www.dpg-verhandlungen.deVerhandlungen der Deutschen Physikalischen Gesellschaft
#MachineLearning#CondensedMatter
Öffentlich *
j_bertolotti

#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

Edit: The diatomic chain animation was wrong (I forgot to multiply by a prefactor which I assumed I could just set to one. I was wrong). Thanks to @narain for pestering me until I found my error! 😃

GIF
GIF
Öffentlich *
Karthik Srinivasan

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

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"

arXiv.orgAn aperiodic monotileA longstanding open problem asks for an aperiodic monotile, also known as an "einstein": a shape that admits tilings of the plane, but never periodic tilings. We answer this problem for topological disk tiles by exhibiting a continuum of combinatorially equivalent aperiodic polygons. We first show that a representative example, the "hat" polykite, can form clusters called "metatiles", for which substitution rules can be defined. Because the metatiles admit tilings of the plane, so too does the hat. We then prove that generic members of our continuum of polygons are aperiodic, through a new kind of geometric incommensurability argument. Separately, we give a combinatorial, computer-assisted proof that the hat must form hierarchical -- and hence aperiodic -- tilings.
#Physics#Maths#Combinatorics
Öffentlich
Steven Thomson

[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: 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!

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