scholarly journals Quantum control and measurement of atomic spins in polarization spectroscopy

2010 ◽  
Vol 283 (5) ◽  
pp. 681-694 ◽  
Author(s):  
Ivan H. Deutsch ◽  
Poul S. Jessen
Keyword(s):  
Quantum Control ◽  
Polarization Spectroscopy ◽  
Atomic Spins

scholarly journals Light-mediated strong coupling between a mechanical oscillator and atomic spins 1 meter apart

Science ◽  
2020 ◽  
Vol 369 (6500) ◽  
pp. 174-179 ◽  
Author(s):  
Thomas M. Karg ◽  
Baptiste Gouraud ◽  
Chun Tat Ngai ◽  
Gian-Luca Schmid ◽  
Klemens Hammerer ◽  
...  
Keyword(s):  
Strong Coupling ◽  
Quantum Physics ◽  
Quantum Control ◽  
Strong Interactions ◽  
Long Distance ◽  
Atomic Spin ◽  
Atomic Spins ◽  
Feedback Networks ◽  
Noise Squeezing ◽  
Opening Up

Engineering strong interactions between quantum systems is essential for many phenomena of quantum physics and technology. Typically, strong coupling relies on short-range forces or on placing the systems in high-quality electromagnetic resonators, which restricts the range of the coupling to small distances. We used a free-space laser beam to strongly couple a collective atomic spin and a micromechanical membrane over a distance of 1 meter in a room-temperature environment. The coupling is highly tunable and allows the observation of normal-mode splitting, coherent energy exchange oscillations, two-mode thermal noise squeezing, and dissipative coupling. Our approach to engineering coherent long-distance interactions with light makes it possible to couple very different systems in a modular way, opening up a range of opportunities for quantum control and coherent feedback networks.

INTEGRABILITY, ENTROPY AND QUANTUM COMPUTATION

1999 ◽  
Vol 10 (07) ◽  
pp. 1205-1228 ◽  
Author(s):  
E. V. KRISHNAMURTHY
Keyword(s):  
Quantum Computation ◽  
Quantum Chaos ◽  
Quantum Control ◽  
Dynamical Evolution ◽  
Open Problems ◽  
Quantum Integrability ◽  
Feynman Path Integrals ◽  
Exact Integrability ◽  
Time Arrow ◽  
Computational Systems

The important requirements are stated for the success of quantum computation. These requirements involve coherent preserving Hamiltonians as well as exact integrability of the corresponding Feynman path integrals. Also we explain the role of metric entropy in dynamical evolutionary system and outline some of the open problems in the design of quantum computational systems. Finally, we observe that unless we understand quantum nondemolition measurements, quantum integrability, quantum chaos and the direction of time arrow, the quantum control and computational paradigms will remain elusive and the design of systems based on quantum dynamical evolution may not be feasible.

Liquid-phase adaptive femtosecond quantum control: Removing intrinsic intensity dependencies

2003 ◽  
Vol 118 (8) ◽  
pp. 3692-3701 ◽  
Author(s):  
T. Brixner ◽  
N. H. Damrauer ◽  
B. Kiefer ◽  
G. Gerber
Keyword(s):  
Liquid Phase ◽  
Quantum Control

scholarly journals Dynamic Quantum Games

2021 ◽  
Author(s):  
Vassili N. Kolokoltsov
Keyword(s):  
Real Time ◽  
Repeated Games ◽  
Dynamic Games ◽  
Quantum Control ◽  
Diffusion Processes ◽  
Natural Class ◽  
Quantum Games ◽  
Technical Problems ◽  
Modern Development ◽  
Starting Point

AbstractQuantum games represent the really twenty-first century branch of game theory, tightly linked to the modern development of quantum computing and quantum technologies. The main accent in these developments so far was made on stationary or repeated games. In this paper, we aim at initiating the truly dynamic theory with strategies chosen by players in real time. Since direct continuous observations are known to destroy quantum evolutions (so-called quantum Zeno paradox), the necessary new ingredient for quantum dynamic games must be the theory of non-direct observations and the corresponding quantum filtering. Apart from the technical problems in organizing feedback quantum control in real time, the difficulty in applying this theory for obtaining mathematically amenable control systems is due partially to the fact that it leads usually to rather non-trivial jump-type Markov processes and/or degenerate diffusions on manifolds, for which the corresponding control is very difficult to handle. The starting point for the present research is the remarkable discovery (quite unexpected, at least to the author) that there exists a very natural class of homodyne detections such that the diffusion processes on projective spaces resulting by filtering under such arrangements coincide exactly with the standard Brownian motions (BM) on these spaces. In some cases, one can even reduce the process to the plain BM on Euclidean spaces or tori. The theory of such motions is well studied making it possible to develop a tractable theory of related control and games, which can be at the same time practically implemented on quantum optical devices.

scholarly journals Spin-Mechanics with Nitrogen-Vacancy Centers and Trapped Particles

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 651
Author(s):  
Maxime Perdriat ◽  
Clément Pellet-Mary ◽  
Paul Huillery ◽  
Loïc Rondin ◽  
Gabriel Hétet
Keyword(s):  
Degrees Of Freedom ◽  
Theoretical Background ◽  
Nitrogen Vacancy ◽  
Full Potential ◽  
Strongly Coupled ◽  
Trapped Particles ◽  
Quantum Regime ◽  
Atomic Spins ◽  
Nitrogen Vacancy Centers ◽  
Mechanical Oscillators

Controlling the motion of macroscopic oscillators in the quantum regime has been the subject of intense research in recent decades. In this direction, opto-mechanical systems, where the motion of micro-objects is strongly coupled with laser light radiation pressure, have had tremendous success. In particular, the motion of levitating objects can be manipulated at the quantum level thanks to their very high isolation from the environment under ultra-low vacuum conditions. To enter the quantum regime, schemes using single long-lived atomic spins, such as the electronic spin of nitrogen-vacancy (NV) centers in diamond, coupled with levitating mechanical oscillators have been proposed. At the single spin level, they offer the formidable prospect of transferring the spins’ inherent quantum nature to the oscillators, with foreseeable far-reaching implications in quantum sensing and tests of quantum mechanics. Adding the spin degrees of freedom to the experimentalists’ toolbox would enable access to a very rich playground at the crossroads between condensed matter and atomic physics. We review recent experimental work in the field of spin-mechanics that employ the interaction between trapped particles and electronic spins in the solid state and discuss the challenges ahead. Our focus is on the theoretical background close to the current experiments, as well as on the experimental limits, that, once overcome, will enable these systems to unleash their full potential.

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