155 research outputs found
Spectroscopy of a synthetic trapped ion qubit
has been identified as an attractive ion for quantum
information processing due to the unique combination of its spin-1/2 nucleus
and visible wavelength electronic transitions. Using a microgram source of
radioactive material, we trap and laser-cool the synthetic = 133
radioisotope of barium II in a radio-frequency ion trap. Using the same, single
trapped atom, we measure the isotope shifts and hyperfine structure of the and
electronic transitions that are needed
for laser cooling, state preparation, and state detection of the clock-state
hyperfine and optical qubits. We also report the
electronic transition isotope shift for
the rare = 130 and 132 barium nuclides, completing the spectroscopic
characterization necessary for laser cooling all long-lived barium II isotopes
Spin gradient thermometry for ultracold atoms in optical lattices
We demonstrate spin gradient thermometry, a new general method of measuring
the temperature of ultracold atoms in optical lattices. We realize a mixture of
spins separated by a magnetic field gradient. Measurement of the width of the
transition layer between the two spin domains serves as a new method of
thermometry which is observed to work over a broad range of lattice depths and
temperatures, including in the Mott insulator regime. We demonstrate the
thermometry in a system of ultracold rubidium atoms, and suggest that
interesting spin physics can be realized in this system. The lowest measured
temperature is 1 nK, indicating that the system has reached the quantum regime,
where insulating shells are separated by superfluid layers.Comment: 5 pages, 3 figures, minor edits for clarit
A scalable, high-speed measurement-based quantum computer using trapped ions
We describe a scalable, high-speed, and robust architecture for
measurement-based quantum-computing with trapped ions. Measurement-based
architectures offer a way to speed-up operation of a quantum computer
significantly by parallelizing the slow entangling operations and transferring
the speed requirement to fast measurement of qubits. We show that a 3D cluster
state suitable for fault-tolerant measurement-based quantum computing can be
implemented on a 2D array of ion traps. We propose the projective measurement
of ions via multi-photon photoionization for nanosecond operation and discuss
the viability of such a scheme for Ca ions.Comment: 4 pages, 3 figure
Canada and the International Labour Organization in the interwar period, 1919-1940.
Dept. of History, Philosophy, and Political Science. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1984 .H838. Source: Masters Abstracts International, Volume: 40-07, page: . Thesis (M.A.)--University of Windsor (Canada), 1984
A Three Dimensional Lattice of Ion Traps
We propose an ion trap configuration such that individual traps can be
stacked together in a three dimensional simple cubic arrangement. The isolated
trap as well as the extended array of ion traps are characterized for different
locations in the lattice, illustrating the robustness of the lattice of traps
concept. Ease in the addressing of ions at each lattice site, individually or
simultaneously, makes this system naturally suitable for a number of
experiments. Application of this trap to precision spectroscopy, quantum
information processing and the study of few particle interacting system are
discussed.Comment: 4 pages, 4 Figures. Fig 1 appears as a composite of 1a, 1b, 1c and
1d. Fig 2 appears as a composite of 2a, 2b and 2
A Modular Quantum System of Trapped Atomic Ions
Scaling up controlled quantum systems to involve large numbers of qubits remains one of the outstanding challenges of quantum information science. One path toward scalability is the use of a modular architecture where adjacent qubits may be entangled with applied electromagnetic fields, and remote qubits may be entangled using photon interference. Trapped atomic ion qubits are one of the most promising platforms for scaling up quantum systems by combining long coherence times with high fidelity entangling operations between proximate and remote qubits. In this thesis, I present experimental progress on combining entanglement between remote atomic ions separated by 1 meter with near-eld entanglement between atomic ions in the same ion trap. I describe the experimental improvements to increase the remote entanglement rate by orders of magnitude to nearly 5 per second. This is the first experimental demonstration where the remote entanglement rate exceeds the decoherence rate of the entangled qubits. The flexibility of creating remote entanglement through photon interference is demonstrated by using the interference of distinguishable photons without sacrificing remote entanglement rate or fidelity. Next I describe the use of master clock in combination with a frequency comb to lock the phases of all laser-induced interactions between remote ion traps while removing optical phase stability requirements. The combination of both types of entanglement gates to create a small quantum network are described. Finally, I present ways to mitigate cross talk between photonic and memory qubits by using different trapped ion species. I show preliminary work on performing state detection of nuclear spin 0 ions by using entanglement between atomic ion spin and photon polarization. These control techniques may be important for building a large-scale modular quantum system
Magnetic super-exchange with ultra cold atoms in spin dependent optical lattices
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Physics, 2009.Cataloged from PDF version of thesis.Includes bibliographical references (p. 65-68).The methods of atomic physics offer a unique opportunity to study strongly correlated many body systems. It is possible to confine BECs in periodic optical lattices to form an analog of a solid state system. The study of these cold atoms in optical lattice systems may prove a very useful testing ground for novel states of matter, testing fundamental condensed matter theory, and may help illuminate a possible connection between the mechanism behind high temperature superconductivity and quantum magnetism. This thesis will focus on trapping cold bosonic atoms in spin dependent optical lattices to engineer a system that behaves according to the Hubbard model. By loading the atoms into a state dependent lattice, it may be possible to explore the full phase space of the Heisenberg model and see magnetic super exchange-driven magnetic ordering in a variety of lattice geometries. The aim of this thesis is primarily to explore some of the tools that may be needed accomplish this task.by David Hucul.S.M
- …