Spin liquids in Rydberg atom arrays in cavities

What is our proposal for the realization of spin liquid?

We consider an atom array held by optical tweezers and placed in an optical cavity. The cavity consists of two mirrors placed on the opposite sides of the system. The photons which normally would escape the system (at least some of them) will bounce back and forth between the mirrors. In such a configuration, the distance between atoms becomes irrelevant and the probability of an excitation hopping between any two atoms becomes the same.

The second ingredient is that the excited state of the atoms would be a Rydberg state – a very high-energy state where the electron is far away from the nucleus. The atoms in Rydberg states interact strongly by van der Waals forces. In our case it would mean that two excitations will have much higher energy when they are at nearest-neighboring atoms than if they are far away.

This setting seems much different from usual crystals. In the typical material, the electrons are much more likely to hop between nearest-neighboring atoms than far-away ones, while in our case they would be able hop arbitrarily far with the same probability. But it turns out that there is in equivalence between such “infinite-range hopping + Rydberg” model and the Heisenberg model, commonly used to describe magnets, including the frustrated ones.
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#Physics #Quantum #TopologicalOrder #CondMat #CondensedMatter #QuantumOptics #Science

Juliane von Wrangel is a PhD student in the “10 m Prototype” group

Together with her colleagues she is building a 10-metre interferometer to overcome the fundamental limits of measurement accuracy imposed by quantum mechanics.

https://www.aei.mpg.de/305613/juliane-von-wrangel

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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Frauke Modugno is a PhD student in the “Quantum Control” group, who works for @DESY as part of her work for the German Centre for Astrophysics (DZA).

Her area of research are surfaces and materials for specialized optics to improve detection sensitivity for applications in quantum metrology and gravitational-wave detection.

https://www.aei.mpg.de/1214294/frauke-modugno

Dr. Mariia Matiushechkina is a postdoctoral researcher in the “Quantum Control” group.

Her research runs at the border of the classical and quantum worlds. She investigates micro-mechanical systems that are able to detect very small light pressure and to reveal quantum-mechanical uncertainties. After investigating plenty micro- and nano-structures I had a chance to improve my knowledge of metamaterials. She has designed a highly reflective metastructure that exhibits low mechanical noise for the future implementation in gravitational-wave detectors.

https://www.aei.mpg.de/884924/mariia-matiushechkina

Lea Richtmann, a PhD student in the “Quantum Control” group works on a quantum optical testbed for quantum machine learning

https://www.aei.mpg.de/883820/lea-richtmann

Edit: Fixed broken link

Prof. Dr. Michèle Heurs is a professor of experimental physics at @unihannover and leads the “Quantum Control” group.

She works in the field of quantum optics, in particular in non-classical laser interferometry, quantum metrology, and quantum opto-mechanics. Her group works on making (laser) light that is better than nature would like you to be able to have. It’s called „squeezed light“, and the group uses it for precision measurements. They exploit the Heisenberg uncertainty principle to reduce the noise in the measurement quantity they’re interested in, at the cost of increasing the noise in another (uninteresting one). This allows them to increase the precision of measurements to below the quantum level.

Examples of such sensitive measurements are gravitational-wave detection, where quantum noise already limits the measurement sensitivity over much of the detection band, but also applications in ultra-high precision spectroscopy, and quantum information, amongst others.

https://www.aei.mpg.de/305873/michele-heurs

Más vale tarde que nunca. Fijo mi #presentacion

Soy Antonio, y el #perro tan adorable de mi foto de perfil se llama Zizek.

Soy investigador en Óptica Cuántica . #quantumoptics

https://arxiv.org/search/physics?searchtype=author&query=Ganfornina-Andrades,+A

En mi tiempo libre leo ensayos académicos sobre juegos y diseño los míos aquí #gamedev

https://antonio-california-games.itch.io/

Me gusta la #poesia (en especial las obras de Sylvia Plath, Rainer Maria Rilke, y William Blake), los #vídeojuegos, y #cocinar (me da mucha paz mental).

Quantum simulation of topological orders

In the previous posts, I was talking a lot about complex quantum states that we aim to study in the QUINTO project: topological orders, in particular spin liquids. Now, let us see how quantum optics can help us in this endeavour.

Topological orders can be hard to find. Not all of them – one particular class, “fractional quantum Hall states”, can be created in the lab by applying very strong magnetic field to electrons confined in two dimensions. But others, such as spin liquids, remain elusive, even though scientists proposed some materials in which spin liquids might occur.

Moreover, with solid-state materials, we don’t usually have enough control to manipulate individual anyons as precisely as we would want (even though impressive experiments were performed with tiny anyon colliders and anyon interferometers in the quantum Hall systems).

An alternative is to assemble a quantum system – a “quantum simulator” from scratch, piece by piece, precisely controlling its parameters. For example, it is possible to “catch” a single atom with a laser beam – a so-called “optical tweezer”. The radiation pressure of the beam “traps” the atom in the point where the light is strongest, i.e. where the beam is focused. Such atoms can then be arranged in arrays resembling crystals.

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#TopologicalOrder #Physics #Science #Quantum #QuantumSimulation #QuantumPhysics #QuantumOptics