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Many-body Quantum Dynamics

Cavendish Laboratory
 

We use ultracold atoms as quantum simulators for many-body phenomena and as quantum sensors, in particular for fundamental physics.

 

Quantum Simulation - More is different

We are studying many-body phenomena at the interface between quantum optics and solid-state physics. Following a statement by P.W. Anderson, "More is Different", genuine many-body phenomena are emergent phenomena that only appear when many particles come together, typical examples being superfluidity or magnetism.

 

Quantum Sensors

The humble atom is nature's most powerful quantum sensor, and its unparalleled precision is harnessed in atomic clocks to literally define our time. A new and upcoming development are plans to exploit large-scale atom interferometers, where baselines can range from 10m to km- and larger scales, that will offer unprecedented sensitivity to detect gravitational waves in the mid-frequency range, search for ultra-light dark matter, and hunt for unknown physics. 
We are part of the AION collaboration that is developing a new experimental platform to perform interferometry with ultracold strontium atoms. 

 

Tools

Ultracold atoms

We are working with several atomic species, namely Rubidium, Potassium (bosonic & fermionic) and Strontium, each providing different complementary capabilities. Potassium and Potassium-Rubidium mixtures host a range of well-characterised Feshbach resonances and enable tuneable quantum gases and mixtures, while Strontium provides an ultra-narrow clock transition that enables atomic clocks and precision interferometry.
We develop and use novel optical trapping geometries ranging from novel optical lattices over cooling and transport traps to arrays of microtraps and optical tweezers.

 

Ultracold Atoms in optical lattices

We study many-body phenomena using ultracold atoms, that is Bose-Einstein condensates and degenerate Fermi gases, which we load into optical lattices. These periodic (or quasiperiodic) optical potentials are analogous to the electrostatic potential felt by electrons in a conventional solid. Thereby, we effectively build a quantum simulator for condensed matter physics, where we can study many-body physics in a very clean and precisely controlled system and have all the tools from quantum optics at our disposal.

 

3D Lattice structure generated by three retroreflected laser beams

 

Many-body Dynamics

In particular, we can follow the dynamics of the system in real time and observe its non-equilibrium dynamics, which is typically an even richer problem than the equilibrium states.

In addition, the underlying quantum optics toolbox with its various fast modulation techniques enables us to synthesize genuinely new many-body systems using Floquet engineering and to thereby create novel effects.

  • Strongly-correlated systems

  • Topological systems

  • Band-structure engineering

  • Out-of-equilibrium dynamics

  • Quantum quenches

  • Disordered Systems / Many-body localization

 

Projects

Latest news

IOP Joseph Thomson Medal

22 December 2023

Professor Ulrich Schneider received the IOP 2023 Joseph Thomson Medal and Prize for groundbreaking experiments on the collective dynamics of quantum gases in optical lattices, including fundamental studies of localization effects in both disordered and quasicrystalline systems. More information at: https://www.iop.org/...

Postdoc Positions available

1 July 2023

We have two experimental postdoc opportunities on many-body physics in Optical Quasicrystals and on being part of the UK Quantum Technology Hub and developing optical optical-lattice and tweezer-based Quantum Simulators . More information at: https://www.jobs.cam.ac.uk/job/41624/ Applications close on 15/8/23.

Observing the two-dimensional Bose glass in an optical quasicrystal

2 March 2023

Our latest work on observing the two-dimensional Bose glass in our optical quasicrystal is now on the Arxiv: Arxiv:2303.00737 . We could not only observe the Bose glass and the phase transition between Bose glass and superfluid, but could furthermore experimentally establish the non-ergodic character of the Bose glass...

Hubbard Models for Quasicrystalline Potentials

13 October 2022

Our latest work on creating Hubbard Models for Quasicrystalline Potentials is now on the Arxiv (2210.05691). In it, we present a numerical method for constructing the Hubbard Hamiltonian of non-periodic potentials without making use of Bloch's theorem, and then apply it to the eightfold rotationally symmetric 2D optical...

AION Vacuum system arrived

4 July 2022

The AION experiment reached an important first milestone with the UHV vacuum chamber having been delivered. Next stop: laser cooled Strontium. aion_uhv_chamber.jpg