#QuantumOptics

2025-12-09

La lumière cache un secret magnétique : le champ magnétique de la lumière influencerait la matière. Mais... l’Effet Faraday mériterait peut-être d’être réécrit. geo.fr/sciences/l-effet-farada

MPI for Gravitational Physicsmpi_grav@academiccloud.social
2025-08-05

🎬 Great new film 🎞️

Our @unihannover colleagues have produced a film about quantum optics and gravitational physics research, featuring inspiring pictures from several of our labs.

🎞️ youtube.com/watch?v=otNPNzYwBpA

🎞️ inv.nadeko.net/watch?v=otNPNzY

German and English subtitles are available.

#QuantumOptics #GravitationalPhysics #Hannover #Research #LISA #GRACE #GRACEFollowOn #GravitationalWaves

Photo with two persons in lab clothing and laser protection goggles working on a complicated looking experiment. Text at the bottom (in German) reads “Research focus quantum optics and gravitational physics at Leibniz University Hannover”.
2025-05-13

We just submitted the first QUINTO draft of paper to a journal. Let's see what the editors and reviewers think.

The paper is about fractional quantum Hall states in atomic arrays. Here is the popular summary we submitted alongside:

"When atoms are arranged in a regular, dense array, their response to light can change drastically. The photons can bounce between the atoms, getting absorbed and re-emitted again and interfering with themselves. This field of quantum optics with atomic arrays is of active interest. Due to interactions, the limit of many absorbed photons generally remains hard to model, but at the same time may result in new, counterintuitive physical phenomena. In the search for ways to understand such systems, we can look for analogies in condensed matter physics, where the behavior of many interacting particles (electrons in this case) has been studied for decades. Here, we report on finding such an analogy between the behavior of few photons absorbed by an array and peculiar many-electron quantum states known as fractional quantum Hall (FQH) states. FQH states display many counterintuitive properties -- for example the electrons behave like they decomposed into pieces (e.g. "one third of an electron"), even though we know that in reality they are indivisible. Now we know that photons in arrays can behave similarly."

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#physics #science #CondensedMatterPhysics #CondensedMatter #condMat #QuantumOptics #Quantum @physics

The abstract of the paper with "PREPRINT" written with big letters on top of it.
2025-04-30

We just came back from the "Light-Matter Interactions and Collective Effects" workshop in Paris. We heard some interesting talks on how quantum emitters (not only atoms, but also e.g. molecules and quantum dots) interact with each other and how people try to arrange them into arrays (like, putting chains of molecules inside a carbon nanotube). Darrick (my boss and supervisor of the project) gave a talk on spin liquids, while I presented a poster on fractional quantum Hall states in atom arrays.

#physics #quantum #science #QuantumOptics #CondensedMatter #CondMat

Entrance to Ecole Normale Superieure Paris-Saclay - the site of the conference
Geekoogeekoo
2025-04-24

A new coronagraph design unveils Earth-like exoplanets hidden in starlight, bringing us closer to finding life beyond Earth.

geekoo.news/blinding-the-stars

2025-04-11

🎉 Congratulations to Immanuel Bloch, MCQST co-Spokesperson, for receiving the first #HightechPreise2025 of the Bavarian Prime Minister recognizing his pioneering work in experimental quantum sciences.

➡️ Read more: mcqst.de/news-and-events/news/
📸 StMWK / A. Gebert

#QuantumOptics #QuantumSciece
#HightechBayern

2025-04-07

We are excited to welcome Prof. Mete Atatüre as a plenary speaker at ECAMP15! A leading expert in solid-state quantum optics, his research focuses on spin-photon coupling for quantum networks and many-body physics in atomically-thin materials. As Head of the Cavendish Laboratory at the University of Cambridge, he leads pioneering efforts in quantum sensing applications.

#ECAMP15 #QuantumOptics #cambridgeuniversity #Physics #meteatatüre #cavendishlaboratory

2025-03-31

Fractional quantum Hall states in atom arrays

Our second approach to create a topological order in atom arrays is to focus on a different kind of topological order: fractional quantum Hall (FQH) states. These were first discovered in condensed matter. It is possible to confine electrons to move in two-dimensions only (such as in the 2D material graphene or in so-called metal-oxide-semiconductor transistors) and then put them in a strong perpendicular magnetic fields. The electrons then move in circles (so-called “cyclotron motion”), but since they are quantum objects, only some values of radius are allowed. Thus, the energy can only take certain fixed values (we call them “Landau levels”). There are however different possibilities of an electron having the same energy, because the center of the orbit can be located in different places – we say that Landau levels are “degenerate”. And when there is degeneracy, the interaction between electrons becomes very important. Without interactions, there are many possible ways of arranging electrons within a Landau level, all with the same energy. In the presence of interactions, some arrangements become preferred – and it turns out those correspond to topological orders known as the FQH states. Such systems host anyons which look like fractions of an electron – like somehow the electron split into several parts.

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#Physics #science #TopologicalOrder #Quantum #QuantumOptics #CondensedMatter #CondMat #cond_mat #QuantumHall

On the left: a hexagonal array of atoms (red balls with small arrows arranged in the xy plane) in a magnetic field (big arrow in the z direction). On the right: the energy levels of each atom: black bar on the bottom denoting the ground state, dashed black line denoting the frequency of atomic transition, and two bars denoting excited states: red bar below the dashed line and blue bar above the dashed line. The distance between the dashed line and each of the bar is mu*B. Each of the excited states is connected with the ground state with double-sided arrow in respective colour, denoting the fact that it can absorb and emit circularly polarized light (red and blue correspond to opposite circular polarizations).The figure comes from the following paper: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.119.023603
2025-03-10

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

A tweezer array in a cavity. The cavity is the two mirrors on left and right trapping a yellow beam of light between them. Inside the cavity, there are several atoms arranged in a “star of David” pattern (a small instance of the frustrated kagome lattice). The atoms are held by optical tweezers (vertical red beams of light)
2025-02-13

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.

ℹ️ aei.mpg.de/305613/juliane-von-

#IDWGS #WomenInSTEM #WomenInScience #Physics #PhD #QuantumMechanics #QuantumOptics #Research #Hannover

2025-02-12

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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2025-02-12

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.

ℹ️ aei.mpg.de/1214294/frauke-modu

#IDWGS #WomenInSTEM #WomenInScience #Physics #PhD #QuantumOptics #GravitationalWaves #Research #Hannover

2025-02-12

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.

ℹ️ aei.mpg.de/884924/mariia-matiu

#IDWGS #WomenInSTEM #WomenInScience #Physics #PhD #QuantumOptics #GravitationalWaves #Research #Hannover

2025-02-11

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

ℹ️ aei.mpg.de/883820/lea-richtman

Edit: Fixed broken link

#IDWGS #WomenInSTEM #WomenInScience #Physics #PhD #QuantumMachineLearning #QuantumOptics #Research #Hannover

2025-02-11

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.

ℹ️ aei.mpg.de/305873/michele-heur

#IDWGS #WomenInSTEM #WomenInScience #Physics #QuantumOptics #SqueezedLight #Laser #Professor #Research #Hannover

Antonio Ganfornina Andradeswadabadah
2025-02-02

Más vale tarde que nunca. Fijo mi

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

Soy investigador en Óptica Cuántica 🔬💻.

arxiv.org/search/physics?searc

En mi tiempo libre leo ensayos académicos sobre juegos y diseño los míos aquí 📝 🕹️

antonio-california-games.itch.

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

2025-01-27

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

A picture taken from the following article: G. Semeghini et al., “Probing topological spin liquids on a programmable quantum simulator”, “Science” 374, 1242-1247 (2021)

Left: a fluorescence image of atoms in the array of tweezers, superimposed over kagome lattice (a ruby lattice, where the atoms are located, is formed by the middle points of the bonds of kagome lattice).

Right: A snapshot of the spin liquid state. The atoms in Rydberg state are denoted by grey ellipses. After mapping to kagome lattice, these atoms can be understood as dimers occupying bonds of the kagome lattice (something analogous to the singlet bonds discussed earlier)

Middle: a diagram showing interaction  between the atoms, as well as the energy levels of an atom: a ground state, a Ryberg level and an arrow from the ground state to somewhere above the Rydberg level, denoting the laser light driving the transitions between levels.
2024-12-11

Yesterday Charlie-Ray Mann gave a talk as a part of the "Many-Body Quantum Optics" program at KITP. Charlie is a postdoc working in the same group as me. Part of presented work (2D numerics which is not directly referenced) was done by me within the QUINTO project. You can listen to the recording of the talk here: online.kitp.ucsb.edu/online/mb

#CondensedMatter #condMat #Cond_mat #TopologicalOrder #SpinLiquid #QuantumOptics #Optics #Physics #ColdAtoms #Science

First slide of the talk. Title: "Emergence of Quantum Spin Liquids from Atom-Cavity Interactions", author: Charlie-Ray Mann. Below a schematic picture of an array of atoms held by optical tweezers (vertical laser beams) in an optical cavity (two mirrors on the left and right, and the light confined by the two mirrors). There are circles around two neighboring atoms, signifying the Rydberg blockade interaction. The slide contains also the logo of ICFO (the institute in Barcelona where our group works, as well as the logo of Marie Skłodowska-Curie Action, from which the research was financed).
2024-12-04

We are now in Santa Barbara, California, for a program “Many-body quantum optics” at Kavli Institute for Theoretical Physics. The program is co-organized by the supervisor of QUINTO, prof Darrick Chang, and is aimed at fostering collaborations between the condensed matter and quantum optics researchers. We already had a couple of interesting discussions and are looking forward to more!

#physics #science #CondensedMatter #CondMat #QuantumOptics #quantum

Door with inscription above: "Kohn Hall, Kavli Institute for Theoretical Physics"Some scribbles on the blackboard (including drawings of hexagonal lattice, Haldane Chern insulator model and Hofstadter model)

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