31 research outputs found
Shaking-induced dynamics of cold atoms in magnetic traps
We describe an experiment in which cold rubidium atoms, confined in an elongated magnetic trap, are excited
by transverse oscillation of the trap center. The temperature after excitation exhibits resonance as a function of
the driving frequency. We measure these resonances at several different trap frequencies. In order to interpret the
experiments, we develop a simple model that incorporates both collisions between atoms and the anharmonicity
of the real three-dimensional trapping potential. As well as providing a precise connection between the transverse
harmonic oscillation frequency and the temperature resonance frequency, this model gives insight into the heating
and loss mechanisms and into the dynamics of driven clouds of cold trapped atoms
Single atom quantum walk with 1D optical superlattices
A proposal for the implementation of quantum walks using cold atom technology
is presented. It consists of one atom trapped in time varying optical
superlattices. The required elements are presented in detail including the
preparation procedure, the manipulation required for the quantum walk evolution
and the final measurement. These procedures can be, in principle, implemented
with present technology.Comment: 6 pages, 7 figure
Generating Single Microwave Photons in a Circuit
Electromagnetic signals in circuits consist of discrete photons, though
conventional voltage sources can only generate classical fields with a coherent
superposition of many different photon numbers. While these classical signals
can control and measure bits in a quantum computer (qubits), single photons can
carry quantum information, enabling non-local quantum interactions, an
important resource for scalable quantum computing. Here, we demonstrate an
on-chip single photon source in a circuit quantum electrodynamics (QED)
architecture, with a microwave transmission line cavity that collects the
spontaneous emission of a single superconducting qubit with high efficiency.
The photon source is triggered by a qubit rotation, as a photon is generated
only when the qubit is excited. Tomography of both qubit and fluorescence
photon shows that arbitrary qubit states can be mapped onto the photon state,
demonstrating an ability to convert a stationary qubit into a flying qubit.
Both the average power and voltage of the photon source are characterized to
verify performance of the system. This single photon source is an important
addition to a rapidly growing toolbox for quantum optics on a chip.Comment: 6 pages, 5 figures, hires version at
http://www.eng.yale.edu/rslab/papers/single_photon_hires.pd
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Measuring the stability of fundamental constants with a network of clocks
The detection of variations of fundamental constants of the Standard Model would provide us with compelling evidence of new physics, and could lift the veil on the nature of dark matter and dark energy. In this work, we discuss how a network of atomic and molecular clocks can be used to look for such variations with unprecedented sensitivity over a wide range of time scales. This is precisely the goal of the recently launched QSNET project: A network of clocks for measuring the stability of fundamental constants. QSNET will include state-of-the-art atomic clocks, but will also develop next-generation molecular and highly charged ion clocks with enhanced sensitivity to variations of fundamental constants. We describe the technological and scientific aims of QSNET and evaluate its expected performance. We show that in the range of parameters probed by QSNET, either we will discover new physics, or we will impose new constraints on violations of fundamental symmetries and a range of theories beyond the Standard Model, including dark matter and dark energy models
Measuring the stability of fundamental constants with a network of clocks
The detection of variations of fundamental constants of the Standard Model would provide us with compelling evidence of new physics, and could lift the veil on the nature of dark matter and dark energy. In this work, we discuss how a network of atomic and molecular clocks can be used to look for such variations with unprecedented sensitivity over a wide range of time scales. This is precisely the goal of the recently launched QSNET project: A network of clocks for measuring the stability of fundamental constants. QSNET will include state-of-the-art atomic clocks, but will also develop next-generation molecular and highly charged ion clocks with enhanced sensitivity to variations of fundamental constants. We describe the technological and scientific aims of QSNET and evaluate its expected performance. We show that in the range of parameters probed by QSNET, either we will discover new physics, or we will impose new constraints on violations of fundamental symmetries and a range of theories beyond the Standard Model, including dark matter and dark energy models
Single atoms in optical traps
We present a brief overview of optical trapping experiments of individual neutral atoms. Then we describe in more details an experiment using a very small optical dipole trap, that is designed to store and manipulate individual atoms. Due to the very small dipole trap volume, a "collisional blockade" mechanism locks the average number of trapped atoms on the value 0.5 over a large range of loading rates. We study this regime experimentally, and we describe methods to measure the oscillation frequencies and the temperature of a single atom in the trap with a high accuracy
Experiments on a videotape atom chip: fragmentation and transport studies
This paper reports on experiments with ultracold rubidium atoms confined in microscopic magnetic traps created using a piece of periodically magnetized videotape mounted on an atom chip. The roughness of the confining potential is studied with atomic clouds at temperatures of a few μK and at distances between 30 and 80 μm from the videotape-chip surface. The inhomogeneities in the magnetic field created by the magnetized videotape close to the central region of the chip are characterized in this way. In addition, we demonstrate a novel transport mechanism whereby we convey cold atoms confined in arrays of videotape magnetic micro-traps over distances as large as ~1 cm parallel to the chip surface. This conveying mechanism enables us to survey the surface of the chip and observe potential-roughness effects across different regions
High-resolution spectroscopy of sub-wavelength conned molecular gases
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A frequency-doubled laser system producing ns pulses for rubidium manipulation
We have constructed a pulsed laser system for the manipulation of cold Rb
atoms. The system combines optical telecommunications components and frequency
doubling to generate light at 780 nm. Using a fast, fibre-coupled intensity
modulator, output from a continuous laser diode is sliced into pulses with a
length between 1.3 and 6.1 ns and a repetition frequency of 5 MHz. These pulses
are amplified using an erbium-doped fibre amplifier, and frequency-doubled in a
periodically poled lithium niobate crystal, yielding a peak power up to 12 W.
Using the resulting light at 780 nm, we demonstrate Rabi oscillations on the F
= 2 F=3-transition of a single 87Rb atom.Comment: 5 pages, 5 figure