18 research outputs found
A quantum information processor with trapped ions
Quantum computers hold the promise to solve certain problems exponentially faster than their classical counterparts. Trapped atomic ions are among the physical systems in which building such a computing device seems viable. In this work we present a small-scale quantum information processor based on a string of [superscript 40]Ca[superscript +] ions confined in a macroscopic linear Paul trap. We review our set of operations which includes non-coherent operations allowing us to realize arbitrary Markovian processes. In order to build a larger quantum information processor it is mandatory to reduce the error rate of the available operations which is only possible if the physics of the noise processes is well understood. We identify the dominant noise sources in our system and discuss their effects on different algorithms. Finally we demonstrate how our entire set of operations can be used to facilitate the implementation of algorithms by examples of the quantum Fourier transform and the quantum order finding algorithm.United States. Office of the Director of National Intelligence (United States. Army Research Office Grant W911NF-10-1-0284
An Open-System Quantum Simulator with Trapped Ions
The control of quantum systems is of fundamental scientific interest and
promises powerful applications and technologies. Impressive progress has been
achieved in isolating the systems from the environment and coherently
controlling their dynamics, as demonstrated by the creation and manipulation of
entanglement in various physical systems. However, for open quantum systems,
engineering the dynamics of many particles by a controlled coupling to an
environment remains largely unexplored. Here we report the first realization of
a toolbox for simulating an open quantum system with up to five qubits. Using a
quantum computing architecture with trapped ions, we combine multi-qubit gates
with optical pumping to implement coherent operations and dissipative
processes. We illustrate this engineering by the dissipative preparation of
entangled states, the simulation of coherent many-body spin interactions and
the quantum non-demolition measurement of multi-qubit observables. By adding
controlled dissipation to coherent operations, this work offers novel prospects
for open-system quantum simulation and computation.Comment: Pre-review submission to Nature. For an updated and final version see
publication. Manuscript + Supplementary Informatio
Design of a dual species atom interferometer for space
Atom interferometers have a multitude of proposed applications in space
including precise measurements of the Earth's gravitational field, in
navigation & ranging, and in fundamental physics such as tests of the weak
equivalence principle (WEP) and gravitational wave detection. While atom
interferometers are realized routinely in ground-based laboratories, current
efforts aim at the development of a space compatible design optimized with
respect to dimensions, weight, power consumption, mechanical robustness and
radiation hardness. In this paper, we present a design of a high-sensitivity
differential dual species Rb/Rb atom interferometer for space,
including physics package, laser system, electronics and software. The physics
package comprises the atom source consisting of dispensers and a 2D
magneto-optical trap (MOT), the science chamber with a 3D-MOT, a magnetic trap
based on an atom chip and an optical dipole trap (ODT) used for Bose-Einstein
condensate (BEC) creation and interferometry, the detection unit, the vacuum
system for mbar ultra-high vacuum generation, and the
high-suppression factor magnetic shielding as well as the thermal control
system. The laser system is based on a hybrid approach using fiber-based
telecom components and high-power laser diode technology and includes all laser
sources for 2D-MOT, 3D-MOT, ODT, interferometry and detection. Manipulation and
switching of the laser beams is carried out on an optical bench using Zerodur
bonding technology. The instrument consists of 9 units with an overall mass of
221 kg, an average power consumption of 608 W (819 W peak), and a volume of 470
liters which would well fit on a satellite to be launched with a Soyuz rocket,
as system studies have shown.Comment: 30 pages, 23 figures, accepted for publication in Experimental
Astronom
STE-QUEST - Test of the Universality of Free Fall Using Cold Atom Interferometry
In this paper, we report about the results of the phase A mission study of the atom
interferometer instrument covering the description of the main payload elements, the
atomic source concept, and the systematic error sources
Optical Metrology Terminal for satellite-to-satellite laser ranging
Optical Metrology Terminal for satellite-to-satellite laser rangin
Optical metrology terminal for satellite-to-satellite laser ranging
Interferometric laser ranging is an enabling technology for high-precision satellite-to-satellite tracking within the context of earth observation, gravitational wave detection, or formation flying. In orbit, the measurement system is affected by environmental influences, particularly satellite attitude jitter and temperature fluctuations, demanding an instrument design, which has a high level of thermal stability and is insensitive to rotations around the satellite's center of mass. Different design approaches for a heterodyne dynamic laser ranging instrument have been combined to a new improved design concept that involves the inherent beam tracking capabilities of a retroreflector into a mono-axial configuration with nanometer accuracy. In order to facilitate the accommodation onboard a future satellite mission, the design allows for a continuously adjustable flexible phase center position. To cover large inter-spacecraft distances, the instrument design comprises an active transponder system, featuring a two-dimensional beam steering mechanism to align a local, strong laser to the (weak) input beam without affecting the measurement path.
To this end, a dynamic laser ranging instrument is presented, which has compact dimensions and is fully integrated on a single Zerodur baseplate. The instrument performance will be evaluated in a dedicated test setup providing a flat-top beam simulating the laser beam received from a distant spacecraft, including a beam steering subsystem, which allows for monitoring of pathlength variations when the angle of incidence at the optical instrument is changing
Architecture and performance analysis of an optical metrology terminal for satellite-to-satellite laser ranging
Interferometric laser ranging is an enabling technology for high-precision satellite-to-satellite tracking
within the context of earth observation, gravitational wave detection, or formation flying. In orbit, the
measurement system is affected by environmental influences, particularly satellite attitude jitter and temperature fluctuations, imposing an instrument design with a high level of thermal stability and insensitivity to rotations around the spacecraft center of mass. The new design concept presented here combines
different approaches for dynamic heterodyne laser ranging and features the inherent beam tracking capabilities of a retroreflector in a mono-axial configuration. It allows for a continuously adjustable distance
between the optical bench and the location of its fiducial point, facilitating future inter-satellite tracking
with nanometer accuracy, e.g., the next-generation gravity mission
Interferometrischer Messkopf zur dynamischen Laser-Entfernungsmessung
Die Laserinterferometrie gilt in der Raumfahrt als vielversprechende Technologie zur dynamischen Abstandsmessung zwischen Satelliten, besonders im Hinblick auf Missionen zur Erdbeobachtung, Detektion von Gravitationswellen und Formationsflügen. Verschiedene Konzepte für ein heterodynes, dynamisches Laser-Entfernungsmessgerät mit Nanometergenauigkeit wurden auf ihre Nutzbarkeit für Gravitations-Missionen der nächsten Generation untersucht und hinsichtlich ihrer Messgenauigkeit, Baugröße, Flexibilität und Komplexität verglichen. Darauf aufbauend wird ein monostatisches Instrumentendesign vorgestellt, bei dem sich die Laserstrahlen auf der direkten Sichtverbindung zwischen den Satelliten ausbreiten, wobei innerhalb des Instruments eine bi-statische Strahlführung Anwendung findet. Die tatsächliche Leistungsfähigkeit soll in einer eigens dafür entwickelten Testumgebung vermessen werden. Zur leichteren Unterbringung in zukünftigen Satellitenmissionen ermöglicht das Instrumentendesign einen frei wählbaren Abstand vom Messkopf zum Phasenzentrum und kann vollständig auf einer kompakten optischen Bank integriert werden. Zuwendung des DLR mit Mitteln des BMWi unter dem Förderkennzeichen 50EE140
Experimental Characterization of Quantum Dynamics Through Many-Body Interactions
We report on the implementation of a quantum process tomography technique known as direct characterization of quantum dynamics applied on coherent and incoherent single-qubit processes in a system of trapped [superscript 40]Ca[superscript +] ions. Using quantum correlations with an ancilla qubit, direct characterization of quantum dynamics reduces substantially the number of experimental configurations required for a full quantum process tomography and all diagonal elements of the process matrix can be estimated with a single setting. With this technique, the system’s relaxation times T[subscript 1] and T[subscript 2] were measured with a single experimental configuration. We further show the first, complete characterization of single-qubit processes using a single generalized measurement realized through multibody correlations with three ancilla qubits