Dr. Stephan Dürr
Stephan Dürr
Telefon: +49 89 3 29 05 - 291
Raum: A 2.22
Prof. Dr. Thomas Udem
Thomas Udem
Telefon: +49 89 3 29 05 - 282 // -257
Raum: D 0.21 // D 0.39

kommende Kolloquien

  • The colloquium series will resume at the beginning of the next term in April/October.



Die Gastvorträge im Rahmen des MPQ-Kolloquiums finden von April bis Juli sowie von Oktober bis Januar jeweils dienstags um 14:30 Uhr statt.

Achtung! Ab Oktober 2017 finden die Vorträge, aufgrund der Bauarbeiten, vorübergehend im Interims-Hörsaal, Raum B 0.32 am Max-Planck-Instituts für Quantenoptik statt.

Ansprechpartner für die wissenschaftliche Organisation:

Dr. Stephan Dürr und Dr. Thomas Udem

Wenn Sie einen Vortrag im Livestream verfolgen möchten, ist es nötig, dass Sie sich in eine entsprechende Mailing Liste eintragen. Daraufhin erhalten Sie Instruktionen zum Empfang des Livestreams.


One-dimensional superradiant photonic states for quantum information

Double Feature: One-dimensional superradiant photonic states for quantum information (Dr. Marti Perarnau)

Photonic states with large and fixed photon numbers, such as Fock states, are crucial in quantum technologies but remain an experimentally elusive resource. A potentially simple, deterministic and scalable way to generate these states consists of fully exciting N quantum emitters equally coupled to a common photonic reservoir, which leads to a collective decay known as Dicke superradiance. The emitted N-photon wavepacket turns out to be a highly entangled multimode state, which makes its characterisation challenging, and its potential for quantum information an open question. In this talk, after reviewing the basics of superradiance and 1d waveguide QED, I will show that Dicke superradiant states have a high quantum Fisher information (achieving Heisenberg scaling), implying they enable quantum-enhanced metrology. Then, I will discuss possible effective descriptions of such states, which would allow a clean understanding of their properties. [mehr]

Interacting polar molecules in a spin-decoupled magic trap

Double Feature: Interacting polar molecules in a spin-decoupled magic trap (Frauke Seeßelberg)

Interacting particles with long coherence times are a key ingredient for entanglement generation and quantum engineering. Ultracold polar molecules are promising candidates due to their strong and tunable dipolar interactions as well as their long single-particle lifetimes. They possess many internal degrees of freedom that can be utilized in quantum simulation. Particularly appealing are superpositions of rotational states because they readily give rise to strong, long-range dipolar interactions. In this talk I will introduce a novel trapping technique for rotating polar molecules, nuclear spin-decoupled magic trapping. With this technique we achieve very low single-particle dephasing rates for our fermionic NaK molecules. These allow us not only to obtain record rotational spin coherence times but also to directly observe dipolar interactions in the molecular gas. This paves the way for fascinating future experiments with ultracold polar molecules. [mehr]

The ATLAS laser: from Terrawatt to Petawatt and from MPQ to CALA

Double Feature: The ATLAS laser: from Terrawatt to Petawatt and from MPQ to CALA (Prof. Stefan Karsch)

Abstract will follow shortly... [mehr]

Double Feature: Creating optical Schrödinger‐cat states with a cavity (Bastian Hacker)

Schrödinger's famous cat Gedankenexperiment investigates how the laws of quantum mechanics extend into the macroscopic realm. An experimentally accessible model system in quantum optics is the superposition of two well-distinguishable coherent states - a so-called "cat state" - with a tunable degree of macroscopicity. Applying a high-finesse cavity we demonstrate a new method to create flying optical cat states. They are entangled to a single trapped atom, much like Schrödinger's original cat. I show control over various degrees of freedom of the cat states, which is a great asset for their potential application to continuous-variable quantum computing. [mehr]

Quantum optics using atomic arrays (Prof. Dr. Darrick Chang)

Ensembles of atoms or other quantum emitters are envisioned to be an important component of quantum applications, ranging from quantum memories for light to photon-photon gates to metrology. It has historically been an outstanding challenge to exactly solve for the quantum dynamics of an optical field as it propagates through and interacts with an ensemble. The standard axiomatic approach is to use the one-dimensional Maxwell-Bloch equations, which assume that excited atoms emit independently into unwanted directions. This ignores the wave interference of the emitted light, which depends on correlations between the atoms. [mehr]

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