409 research outputs found
Zero-Point cooling and low heating of trapped 111Cd+ ions
We report on ground state laser cooling of single 111Cd+ ions confined in
radio-frequency (Paul) traps. Heating rates of trapped ion motion are measured
for two different trapping geometries and electrode materials, where no effort
was made to shield the electrodes from the atomic Cd source. The low measured
heating rates suggest that trapped 111Cd+ ions may be well-suited for
experiments involving quantum control of atomic motion, including applications
in quantum information science.Comment: 4 pages, 6 figures, Submitted to PR
Implementation of Grover's Quantum Search Algorithm in a Scalable System
We report the implementation of Grover's quantum search algorithm in the
scalable system of trapped atomic ion quantum bits. Any one of four possible
states of a two-qubit memory is marked, and following a single query of the
search space, the marked element is successfully recovered with an average
probability of 60(2)%. This exceeds the performance of any possible classical
search algorithm, which can only succeed with a maximum average probability of
50%.Comment: 4 pages, 3 figures, updated error discussio
Phase Control of Trapped Ion Quantum Gates
There are several known schemes for entangling trapped ion quantum bits for
large-scale quantum computation. Most are based on an interaction between the
ions and external optical fields, coupling internal qubit states of
trapped-ions to their Coulomb-coupled motion. In this paper, we examine the
sensitivity of these motional gate schemes to phase fluctuations introduced
through noisy external control fields, and suggest techniques to suppress the
resulting phase decoherence.Comment: 21 pages 12 figure
Entanglement of Trapped-Ion Clock States
A M{\o}lmer-S{\o}rensen entangling gate is realized for pairs of trapped
Cd ions using magnetic-field insensitive "clock" states and an
implementation offering reduced sensitivity to optical phase drifts. The gate
is used to generate the complete set of four entangled states, which are
reconstructed and evaluated with quantum-state tomography. An average
target-state fidelity of 0.79 is achieved, limited by available laser power and
technical noise. The tomographic reconstruction of entangled states
demonstrates universal quantum control of two ion-qubits, which through
multiplexing can provide a route to scalable architectures for trapped-ion
quantum computing.Comment: 6 pages, 5 figure
Towards a Deadline-Based Simulation Experimentation Framework Using Micro-Services Auto-Scaling Approach
There is growing number of research efforts in developing auto-scaling algorithms and tools for cloud resources. Traditional performance metrics such as CPU, memory and bandwidth usage for scaling up or down resources are not sufficient for all applications. For example, modeling and simulation experimentation is usually expected to yield results within a specific timeframe. In order to achieve this, often the quality of experiments is compromised either by restricting the parameter space to be explored or by limiting the number of replications required to give statistical confidence. In this paper, we present early stages of a deadline-based simulation experimentation framework using a micro-services auto-scaling approach. A case study of an agent-based simulation of a population physical activity behavior is used to demonstrate our framework
Innovations in Simulation: Experiences with Cloud-based Simulation Experimentation
The amount of simulation experimentation that can be performed in a project can be restricted by time, especially if a model takes a long time to simulate and many replications are required. Cloud Computing presents an attractive proposition to speeding up, or extending, simulation experimentation as computing resources can be hired on demand rather than having to invest in costly infrastructure. However, it is not common practice for simulation users to take advantage of this and, arguably, rather than speeding up simulation experimentation users tend to make compromises by using unnecessary model simplification techniques. This may be due to a lack of awareness of what Cloud Computing can offer. Based on several yearsâ experience of innovation in this area, this article presents our experiences in developing Cloud Computing applications for simulation experimentation and discusses what future innovations might be created for the widespread benefit of our simulation community
Ultrasensitive force and displacement detection using trapped ions
The ability to detect extremely small forces is vital for a variety of
disciplines including precision spin-resonance imaging, microscopy, and tests
of fundamental physical phenomena. Current force-detection sensitivity limits
have surpassed 1 (atto ) through coupling of micro or
nanofabricated mechanical resonators to a variety of physical systems including
single-electron transistors, superconducting microwave cavities, and individual
spins. These experiments have allowed for probing studies of a variety of
phenomena, but sensitivity requirements are ever-increasing as new regimes of
physical interactions are considered. Here we show that trapped atomic ions are
exquisitely sensitive force detectors, with a measured sensitivity more than
three orders of magnitude better than existing reports. We demonstrate
detection of forces as small as 174 (yocto ), with a
sensitivity 390 using crystals of Be
ions in a Penning trap. Our technique is based on the excitation of normal
motional modes in an ion trap by externally applied electric fields, detection
via and phase-coherent Doppler velocimetry, which allows for the discrimination
of ion motion with amplitudes on the scale of nanometers. These experimental
results and extracted force-detection sensitivities in the single-ion limit
validate proposals suggesting that trapped atomic ions are capable of detecting
of forces with sensitivity approaching 1 . We anticipate that
this demonstration will be strongly motivational for the development of a new
class of deployable trapped-ion-based sensors, and will permit scientists to
access new regimes in materials science.Comment: Expanded introduction and analysis. Methods section added. Subject to
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