# Atomic Physics Seminar

I will describe the generation of 20dB spin-squeezed states of half a million 87Rb atoms inside of an optical cavity. From a practical point of view, the generated states enable up to a 100-fold reduction in required averaging times or atom numbers to achieve a given precision. I will explain the implementation of an atomic clock operating 10 dB beyond the standard quantum limit as well as the investigations of entanglement and Bell correlations in this system. I will then describe the demonstration of a new concept we call quantum phase magnification which utilizes optical cavity-aided interactions between atoms to magnify signals to-be-measured. This technique eliminates the need for low noise detection to achieve phase sensitivities beyond the standard quantum limit. I will conclude with future visions.

*stanford*

**Available Downloads:**

Polar molecules offer long-range anisotropic interactions, which are fundamental to a wide variety of phenomena, from ferrofluid behavior to the folding of proteins. Recent demonstrations of cooling and trapping polar molecules have made it possible to study these particles in the quantum regime, making them highly attractive for applications such as quantum information storage and exploring novel condensed matter phases. In this talk, I will report on the quantum control of dipolar fermionic NaK molecules, which we have synthesized in the ground state at ultracold temperatures as low as 300 nK. Using microwaves, we have coherently manipulated not only the rotational states of the molecules, but also the nuclear spin degree of freedom. I will present our observation of nuclear spin coherence times on the scale of 1 second, and discuss its implications for quantum memory and probing new physics via Hertz-level precision spectroscopy.

*MIT*

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High energy short pulse lasers are useful tools for probing the structure and dynamics of materials and accelerating particles. The European Union is investing in a network of laser centers focused on fundamental research called the Extreme Light Infrastructure (ELI). ELI hopes to allow the investigation of new regimes of laser-matter interaction with multi-petawatt laser pulses and unprecedented repetition rates. In this talk I will present one of the facilities currently under development in Prague, Czech Republic. While an overview of the laser systems under development will be given, the primary focus of the talk will be on current techniques and principles of high energy laser amplification.

*ELI project at the Czech Republic.*

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Optical atomic magnetometers are among the most precise magnetic sensors today, reaching sensitivities up to 0.16 fT/sqrt(Hz). While the AC Stark effect is one of the noise sources in atomic magnetometers, it can be utilized to improve these devices. The effect of the vector part of the AC Stark operator on alkali atoms is equivalent to applying a magnetic field in the direction of the light propagation. We use this effect to create an all-optical vector magnetometer with 0.2 pT/sqrt(Hz) sensitivity to the field magnitude and 4 mrad/sqrt(Hz) sensitivity to the field direction, as well as a scalar magnetometer driven by a fictitious rf field with 40 fT/sqrt(Hz) sensitivity.

*Berkeley*

**Available Downloads:**

TBD

*University of Pennsylvania*

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Atomic Hong-Ou-Mandel effect: a mile-stone in Quantum Atom Optics

*Institut d’Optique*

**Available Downloads:**

*NYU*

**Available Downloads:**

*various*

**Available Downloads:**

*Urbana-Champaign*

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Coulomb interactions limit the brightness of charged particle beams. Controlling the effects of nonlinear beam expansion (space charge) and disordered inter-particle scattering is of critical importance for applications ranging from ultrafast electron diffraction to injectors for particle accelerators. In this talk I will show that ultra-cold ion bunches extracted from laser-cooled atoms can be used to observe the effects of Coulomb interactions with unprecedented detail. Arbitrarily shaped bunches are created to reverse the space-charge problem, and excitation of the cold atoms to Rydberg states prior to ionisation reduces the disorder-induced heating effect. I will present our experimental results that demonstrate improved beam brightness and models and simulations of the effects.

*University Melbourne*

**Available Downloads:**