WorldCat Identities

Jin, Deborah S.

Overview
Works: 5 works in 5 publications in 1 language and 10 library holdings
Publication Timeline
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Most widely held works by Deborah S Jin
Strongly interacting Bose-Einstein condensates: Probes and techniques by Juan Manuel Ii Pino( )

1 edition published in 2010 in English and held by 3 WorldCat member libraries worldwide

A dilute gas Bose-Einstein condensate (BEC) near a Feshbach resonance offers a system that can be tuned from the well-understood regime of weak interactions to the complex regime of strong interactions. Strong interactions play a central role in the phenomena of superfluidity in liquid He, and theoretical treatments for this regime have existed since the 1950's. However, these theories have not been experimentally tested as superfluid He offers no similar mechanism with which to tune the interactions. In dilute gas condensates near a Feshbach resonance, where interactions can be tuned, strong interactions have proven difficult to study due to the condensate's metastable nature with respect to the formation of weakly bound molecules. In this thesis, I introduce an experimental system and novel probes of the gas that have been specifically designed to study strongly interacting BECs. I present Bragg spectroscopy measurements that have accessed this regime, as well as proof-of-principle experiments using photon-counting for Bragg spectroscopy at low-momentum. Finally, I show preliminary data using contact spectroscopy, which is a method that could lead to the first measurements of the predicted interaction energies for a dilute Bose gas of atoms in the strongly interacting regime
Bose polarons and rotating gases in an ultracold Bose-Fermi gas mixture of 40K and 87Rb atoms by Ming-Guang Hu( )

1 edition published in 2015 in English and held by 2 WorldCat member libraries worldwide

An ultracold Bose-Fermi gas mixture of 40K and 87Rb atoms has tunable interspecies interactions and therefore provides a fantastic platform for exploring not only few-body physics such as Feshbach molecule formation and Efimov trimers, but also many-body physics including Bose polarons, quantum Hall physics and so on. In this thesis, I present experimental evidence of Bose polarons in cold atoms obtained using radio-frequency spectroscopy to measure the excitation spectrum of fermionic 40K impurities resonantly interacting with a BEC of 87Rb atoms. These Bose polarons originate from the dressing of an impurity coupled to its environment, which is an important paradigm in quantum many-body physics. I also present initial work that launches an exciting new direction for our experiment, which is exploring rotating quantum gases. Goals for this work include studying both rotating Bose and Fermi superfluids with tunable interactions as well as working toward rapidly rotating quantum gases in the quantum Hall regime. For these goals, a new all-optical trap for rotating gases was designed, implemented, and tested using a 87Rb Bose-Einstein condensate
Experimental studies of a degenerate unitary Bose gas by Philip Makotyn( )

1 edition published in 2014 in English and held by 2 WorldCat member libraries worldwide

A dilute Bose-Einstein condensate (BEC) near a Feshbach resonance provides experimental physics with a clean and controllable system to investigate strongly interacting many-body systems. The ability to tune the scattering length allows BECs to be projected onto strong interactions from an initial weakly interacting state. However, historically, studying a bulk 3D strongly interacting BEC has been difficult, as these systems are inherently unstable due to three-body inelastic collisions. Thus, 2D, 1D, lattice confined, and two component Fermi gases were used to explore the strong interactions in an ultracold gas. In this thesis, I present the first measurement of a strongly interacting 3D 85Rb BEC
Measuring local properties of a Fermi gas in the BCS-BEC crossover by Tara E Drake( )

1 edition published in 2015 in English and held by 2 WorldCat member libraries worldwide

This thesis presents experiments probing the physics of strongly interacting fermionic atoms in the BCS-BEC crossover. Ultracold atom experiments bring the ability to arbitrarily tune interatomic interactions, which allows for unprecedented access to the regime of strongly interacting physics. The majority of cold atom experiments, however, are carried out in an atom trap that imprints an inhomogeneous density on the cloud of atoms. Many phenomena, especially the signatures of phase transitions, are significantly modified by this non-uniform density. In this thesis, I present a novel imaging technique that allows us to probe a region of nearly homogeneous density within a larger, inhomogenenous cloud. Using this technique, I present new results for strongly interacting fermionic atoms, including the first measurements of the contact and the occupied spectral function of a homogeneous Fermi gas, and the first direct observation of the ̀̀textbook" momentum distribution of an ideal Fermi gas
A quantum gas of polar molecules in an optical lattice by Steven A Moses( )

1 edition published in 2016 in English and held by 1 WorldCat member library worldwide

Ultracold polar molecules, because of their long-range, spatially anisotropic interactions, are a new quantum system in which to study novel many-body phenomena. In our lab, we have produced the first quantum gas of 40K 87Rb polar molecules. These molecules were found to undergo exothermic chemical reactions, and this led to interesting studies of chemistry near absolute zero. By creating the molecules at individual sites of a 3D optical lattice, we completely suppress these chemical reactions, and the polar molecule gas becomes stable and lives for tens of seconds. This thesis documents our efforts to explore coherent, many-body phenomena resulting from long-range dipolar interactions in the lattice. By encoding a spin-1/2 system in the rotational states of the molecules, we were able to realize spin-exchange interactions based on a spin Hamiltonian, which is one of the first steps in studying quantum magnetism with polar molecules. While this study was the first realization of such coherent dipolar interactions with polar molecules in a lattice, its full potential was limited by the low lattice filling fractions. Using our ability to exquisitely control the initial atomic gas mixture, we loaded a Mott insulator of Rb and a band insulator of K into the lattice. This quantum synthesis approach led to significantly higher molecular filling fractions and represents the first fully connected system of polar molecules in an optical lattice. This low-entropy quantum gas of polar molecules opens the door to interesting quantum simulations, which should be attainable in the next generation of the experiment
 
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Audience level: 0.62 (from 0.57 for Measuring ... to 0.73 for Strongly i ...)

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