scholarly journals Quantum enhanced feedback cooling of a mechanical oscillator using nonclassical light

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Clemens Schäfermeier ◽  
Hugo Kerdoncuff ◽  
Ulrich B. Hoff ◽  
Hao Fu ◽  
Alexander Huck ◽  
...  
Keyword(s):  
Feedback Control ◽  
Laser Cooling ◽  
Mechanical Oscillator ◽  
Fundamental Physics ◽  
Squeezed Light ◽  
Frequency Standards ◽  
Quantum Feedback ◽  
Consequent Reduction ◽  
Light Probe ◽  
Measurement Rate

Abstract Laser cooling is a fundamental technique used in primary atomic frequency standards, quantum computers, quantum condensed matter physics and tests of fundamental physics, among other areas. It has been known since the early 1990s that laser cooling can, in principle, be improved by using squeezed light as an electromagnetic reservoir; while quantum feedback control using a squeezed light probe is also predicted to allow improved cooling. Here we show the implementation of quantum feedback control of a micro-mechanical oscillator using squeezed probe light. This allows quantum-enhanced feedback cooling with a measurement rate greater than it is possible with classical light, and a consequent reduction in the final oscillator temperature. Our results have significance for future applications in areas ranging from quantum information networks, to quantum-enhanced force and displacement measurements and fundamental tests of macroscopic quantum mechanics.

OPTICAL CLOCKS AND FREQUENCY METROLOGY FOR SPACE

2007 ◽  
Vol 16 (12b) ◽  
pp. 2537-2540
Author(s):  
HUGH KLEIN
Keyword(s):  
European Space Agency ◽  
Frequency Standard ◽  
Optical Frequency ◽  
Fundamental Physics ◽  
Frequency Standards ◽  
Space Agency ◽  
Primary Frequency ◽  
Measurement Capabilities ◽  
Science Activities ◽  
Frequency Metrology

Optical frequency standards and femtosecond comb measurement capabilities now rival and in some cases exceed those of microwave devices, with further improvements anticipated. Opportunities are emerging for the application of highly stable and accurate optical frequency devices to fundamental physics space science activities, and the European Space Agency (ESA) has recently commissioned studies on different aspects of optical clocks in space. This paper highlights some examples, including the difficulty of comparing very accurate terrestrial clocks at different locations due to fluctuations of the geoid; by locating a primary frequency standard in space, one could avoid geoid-related gravitational redshifts.

Ultracold atoms and precise time standards

2011 ◽  
Vol 369 (1953) ◽  
pp. 4078-4089 ◽  
Author(s):  
Gretchen K. Campbell ◽  
William D. Phillips
Keyword(s):  
Laser Cooling ◽  
International System ◽  
Microwave Frequency ◽  
Observation Time ◽  
Mass Motion ◽  
Frequency Standards ◽  
Systematic Uncertainties ◽  
System Of Units ◽  
Time Standards ◽  
Atomic Frequency

Experimental techniques of laser cooling and trapping, along with other cooling techniques, have produced gaseous samples of atoms so cold that they are, for many practical purposes, in the quantum ground state of their centre-of-mass motion. Such low velocities have virtually eliminated effects such as Doppler shifts, relativistic time dilation and observation-time broadening that previously limited the performance of atomic frequency standards. Today, the best laser-cooled, caesium atomic fountain, microwave frequency standards realize the International System of Units (SI) definition of the second to a relative accuracy of ≈3×10 −16 . Optical frequency standards, which do not realize the SI second, have even better performance: cold neutral atoms trapped in optical lattices now yield relative systematic uncertainties of ≈1×10 −16 , whereas cold-trapped ions have systematic uncertainties of 9×10 −18 . We will discuss the current limitations in the performance of neutral atom atomic frequency standards and prospects for the future.

scholarly journals Quantum feedback control of a solid-state qubit

2002 ◽  
Vol 66 (4) ◽  
Author(s):  
Rusko Ruskov ◽  
Alexander N. Korotkov
Keyword(s):  
Solid State ◽  
Feedback Control ◽  
Quantum Feedback

Deterministic generation of symmetric multi-qubit Dicke states: an application of quantum feedback control

2015 ◽  
Vol 9 (17) ◽  
pp. 2500-2505 ◽  
Author(s):  
Jia-Hua Wei ◽  
Jian-Hua Huang ◽  
Bo Qi ◽  
Hong-Yi Dai ◽  
Ming Zhang
Keyword(s):  
Feedback Control ◽  
Quantum Feedback ◽  
Dicke States

scholarly journals Development of a space cold atom clock

2020 ◽  
Vol 7 (12) ◽  
pp. 1828-1836
Author(s):  
Wei Ren ◽  
Tang Li ◽  
Qiuzhi Qu ◽  
Bin Wang ◽  
Lin Li ◽  
...  
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Cold Atoms ◽  
Cold Atom ◽  
Deep Space ◽  
Fundamental Physics ◽  
Time Frequency ◽  
Frequency Standards ◽  
Scientific Experiments ◽  
Primary Frequency

Abstract Atomic clocks with cold atoms play important roles in the field of fundamental physics as well as primary frequency standards. Operating such cold atom clocks in space paves the way for further exploration in fundamental physics, for example dark matter and general relativity. We developed a space cold atom clock (SCAC), which was launched into orbit with the Space Lab TG-2 in 2016. Before it deorbited with TG-2 in 2019, the SCAC had been working continuously for almost 3 years. During the period in orbit, many scientific experiments and engineering tests were performed. In this article, we summarize the principle, development and in-orbit results. These works provide the basis for construction of a space-borne time-frequency system in deep space.

scholarly journals Simulation of the complex dynamics of mean-field p -spin models using measurement-based quantum feedback control

2020 ◽  
Vol 102 (2) ◽  
Author(s):  
Manuel H. Muñoz-Arias ◽  
Ivan H. Deutsch ◽  
Poul S. Jessen ◽  
Pablo M. Poggi
Keyword(s):  
Feedback Control ◽  
Complex Dynamics ◽  
Mean Field ◽  
Spin Models ◽  
Quantum Feedback

ATOMIC CLOCK ENSEMBLE IN SPACE: AN UPDATE

2007 ◽  
Vol 16 (12b) ◽  
pp. 2511-2523 ◽  
Author(s):  
C. SALOMON ◽  
L. CACCIAPUOTI ◽  
N. DIMARCQ
Keyword(s):  
Atomic Clock ◽  
Space Station ◽  
Microgravity Environment ◽  
Time Base ◽  
Standard Model Extension ◽  
Fundamental Physics ◽  
Frequency Standards ◽  
Stability And Accuracy ◽  
Microwave Link ◽  
New Generation

Atomic Clock Ensemble in Space (ACES) is a mission in fundamental physics that will operate a new generation of atomic clocks in the microgravity environment of the International Space Station. Fractional frequency stability and accuracy of a few parts in 1016 will be achieved. The on-board time base, distributed on the Earth via a microwave link, will be used to perform space-to-ground as well as ground-to-ground comparisons of atomic frequency standards. Based on these comparisons, ACES will perform fundamental physics tests (Einstein's theories of special and general relativity, the search for drift of fundamental constants, the Standard Model extension and tests of string theories) and develop applications in time and frequency metrology, time scales, geodesy, global positioning and navigation. After an overview of the mission concept and its scientific objectives, the present status of ACES instruments and subsystems will be discussed.

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