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Entanglement Generation in Universal Quantum Dynamics

Periodic Reporting for period 4 - EntangleGen (Entanglement Generation in Universal Quantum Dynamics)

Reporting period: 2021-04-01 to 2021-09-30

Quantum mechanics predicts that many particle systems can reveal much stronger correlations than classically possible. This is known as quantum entanglement and is at the heart of our fundemanetal understanding of many body quantum systems but also to quantum metrology and other quantum enabled technologies. Thus the understanding and reliable generation is essential for future applications in quantum sensing, quantum simulation and quantum computation.

In this project new paths for detection as well as generation of entanglement in many particle systems are investigated. As the experimental platform ultracold Bose gases is used with which the first observation of universal quantum dynamics far from equilibrium, predicted in the context of quantum chromodynamics, as well as the generation and direct detection of spatial Einstein-Podolsky correlations in extended quantum gases has been possible.

The results can be seen as setting the foundations of quantitative experiments with ultracold gases in the quantum field theoretical setting, offering an experiment system for benchmarking quantum field theoretical predictions and the route for a new class of analog simulators.
There have been a number of results obtained on the theoretical and experimental aspects. Here the most important breakthroughs are listed:

1) Demonstration of nonlinear readout as efficient path for utilizing and accessing entanglement with simple standard readout.
Phys.Rev.Lett. 117, 013001 (2015).

2) First demonstration of generation of non-local quantum correlations in ultracold gases.
Science 360, 413 (2018).

3) First demonstration of universal quantum dynamics.
Nature 563, 217 (2018).

4) Extraction of quantum effective actions
Nature Physics 10.1038/s41567-020-0933-6 (2020).

Additional to these results directly connected to the question of generation of entanglement, the developed experimental techniques for precise atom manipulation have been employed for atom trace analysis of Ar39 atoms. These are perfect environmental tracers for determining the age of water and ice. Both aspects have recently been demonstrated.

4) New insight into ocean ventilation close to Cape Verde islands.
Nature Comm. 9, 5046 (2018).

5) First dating of alpine glacier ice with quantum technology.
PNAS 116, 8781 (2019).
All results so far are beyond state of the art at the time and open up new perspectives for generation and detection of entanglement as well as applying the developed experimental techniques for applications in environmental science. New results point to the directions of extending detection schemes beyond pure projective measurements (POVM) as well as the precise detection of quantum field theoretical objects such as the one-particle irreducible four vertex.
Impressions from the Lab