Optomechanics and Quantum Measurement

2020 ◽  
pp. 183-236
Author(s):  
Aashish A. Clerk
Keyword(s):  
Quantum Measurement ◽  
Linear Response ◽  
Quantum Limit ◽  
Langevin Equations ◽  
Driven Cavity ◽  
Cavity System ◽  
Back Action ◽  
Quantum Optomechanics ◽  
Optomechanical Cavity

After a quick review of the basic theory of quantum optomechanical systems, based largely on linearized Heisenberg–Langevin equations, this chapter focuses on selected topics related to quantum measurement and quantum optomechanics. Included are: a comprehensive discussion of the quantum limit on the added noise of a continuous position detector, following the quantum linear response approach; a detailed discussion of the role of noise correlations, and how these can be achieved in an optomechanical cavity (by using squeezed input light, or by modifying the choice of measured output quadrature); and a discussion of back-action evading measurements of a mechanical quadrature, discussing how this can be achieved in a two-tone driven cavity system. The chapter ends with a quick introduction to the theory of conditional continuous quantum measurement, and a discussion on how a back-action evading measurement can be used to produce conditional mechanical squeezed states.

Quantum measurement

Quantum 20/20 ◽  
2019 ◽  
pp. 181-200
Author(s):  
Ian R. Kenyon
Keyword(s):  
Gravitational Waves ◽  
Quantum Measurement ◽  
Input Port ◽  
Quantum Limit ◽  
Photon Flux ◽  
Standard Quantum ◽  
Standard Quantum Limit ◽  
Back Action

Heisenberg’s back action and Robertson’s intrinsic uncertainty are presented. von Neumann’s analysis of quantum measurement is recounted. Advanced LIGO is used as an example of quantum measurement: giant Michelson interferometers achieve sensitivity to motion of 1 part in 1021. The discovery at LIGO of gravitational waves is outlined. Then the standard quantum limit is deduced. The use of cavities in the interferometer arms to increase the photon flux is described. The potential for improvement by squeezing the vacuum at the blank input port is discussed. Prospects for speed interferometry are outlined.

The coupling of single-photon exciton–biexciton quantum dot and cavity

2017 ◽  
Vol 26 (03) ◽  
pp. 1750029 ◽  
Author(s):  
Lina Jaya Diguna ◽  
Yudi Darma ◽  
Muhammad Danang Birowosuto
Keyword(s):  
Correlation Function ◽  
Quantum Dot ◽  
Density Matrix ◽  
High Probability ◽  
Single Photon ◽  
Photon Emission ◽  
Emission Properties ◽  
Proposed Model ◽  
Cavity System

We investigate the influence of multiple excitons on the photon emission properties of a quantum dot (QD)-cavity system via the master equation for the density matrix. We show that in the intermediate to strong coupling regimes, the multiple excitons lead to the suppressed QD emissions as well as the absence of anti-crossing near zero detuning, arising from the interaction between the multiple excitons and cavity. Furthermore, we analyze the role of the cavity-biexciton detuning in the photon emission properties of cavity and exciton through the second-order correlation function. The small cavity-biexciton detuning yields the significant Purcell effect and the high probability of single photon emissions. The proposed model offers the fundamental approach in developing efficient single-photon emitting devices.

scholarly journals Squeezed-light-driven force detection with an optomechanical cavity in a Mach–Zehnder interferometer

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chang-Woo Lee ◽  
Jae Hoon Lee ◽  
Hyojun Seok
Keyword(s):  
Zehnder Interferometer ◽  
Vacuum Field ◽  
Quantum Limit ◽  
Measurement Sensitivity ◽  
Force Detection ◽  
Detection Scheme ◽  
Standard Quantum ◽  
Standard Quantum Limit ◽  
Optomechanical Cavity ◽  
Mach Zehnder Interferometer

Abstract We analyze the performance of a force detector based on balanced measurements with a Mach–Zehnder interferometer incorporating a standard optomechanical cavity. The system is driven by a coherent superposition of coherent light and squeezed vacuum field, providing quantum correlation along with optical coherence in order to enhance the measurement sensitivity beyond the standard quantum limit. We analytically find the optimal measurement strength, squeezing direction, and squeezing strength at which the symmetrized power spectral density for the measurement noise is minimized below the standard quantum limit. This force detection scheme based on a balanced Mach–Zehnder interferometer provides better sensitivity compared to that based on balanced homodyne detection with a local oscillator in the low frequency regime.

Emergence of the geometric phase from quantum measurement back-action

2019 ◽  
Vol 15 (7) ◽  
pp. 665-670 ◽  
Author(s):  
Young-Wook Cho ◽  
Yosep Kim ◽  
Yeon-Ho Choi ◽  
Yong-Su Kim ◽  
Sang-Wook Han ◽  
...  
Keyword(s):  
Quantum Measurement ◽  
Geometric Phase ◽  
Back Action

scholarly journals Getting Information via a Quantum Measurement: The Role of Decoherence

2015 ◽  
Vol 54 (12) ◽  
pp. 4356-4366 ◽  
Author(s):  
Pietro Liuzzo-Scorpo ◽  
Alessandro Cuccoli ◽  
Paola Verrucchi
Keyword(s):  
Quantum Measurement

scholarly journals Mutations in Ribosomal Protein L16 Conferring Reduced Susceptibility to Evernimicin (SCH27899): Implications for Mechanism of Action

2000 ◽  
Vol 44 (3) ◽  
pp. 732-738 ◽  
Author(s):  
Peter V. Adrian ◽  
Wenjun Zhao ◽  
Todd A. Black ◽  
Karen J. Shaw ◽  
Roberta S. Hare ◽  
...  
Keyword(s):  
Ribosomal Protein ◽  
Linear Response ◽  
Rapid Decrease ◽  
Nucleotide Sequence Analysis ◽  
Secondary Effects ◽  
Direct Transformation ◽  
Susceptible Isolate ◽  
Inhibitor Of Protein Synthesis ◽  
Inhibition Studies

ABSTRACT A clinical isolate of Streptococcus pneumoniae (SP#5) that showed decreased susceptibility to evernimicin (MIC, 1.5 μg/ml) was investigated. A 4,255-bp EcoRI fragment cloned from SP#5 was identified by its ability to transform evernimicin-susceptibleS. pneumoniae R6 (MIC, 0.03 μg/ml) such that the evernimicin MIC was 1.5 μg/ml. Nucleotide sequence analysis of this fragment revealed that it contained portions of the S10-spc ribosomal protein operons. The nucleotide sequences of resistant and susceptible isolates were compared, and a point mutation (thymine to guanine) that causes an Ile52-Ser substitution in ribosomal protein L16 was identified. The role of this mutation in decreasing susceptibility to evernimicin was confirmed by direct transformation of the altered L16 gene. The presence of the L16 mutation in the resistant strain suggests that evernimicin is an inhibitor of protein synthesis. This was confirmed by inhibition studies using radiolabeled substrates, which showed that the addition of evernimicin at sub-MIC levels resulted in a rapid decrease in the incorporation of radiolabeled isoleucine in a susceptible isolate (SP#3) but was much less effective against SP#5. The incorporation of isoleucine showed a linear response to the dose level of evernimicin. The incorporation of other classes of labeled substrates was unaffected or much delayed, indicating that these were secondary effects.

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