Quantum coherence in physics and optics

We discuss the influences of two different types of mechanisms of quantum coherence on optical bistability in a semiconductor quantum well structure. In the first mechanism, only quantum coherence induced by the resonant coupling of a strong control laser is considered. In the second mechanism, the decay coherence is taken into account under the condition where the control field is weak. In two different cases, optical bistability can be obtained through choosing appropriate physical parameters. Our studies show quantum coherence makes the optical nonlinear effect of the system become stronger, which takes an important role in the process of generating optical bistability. A semiconductor quantum well with flexibility and easy integration in design could potentially be exploited in real solid-state devices.We discuss the influences of two different types of mechanisms of quantum coherence on optical bistability in a semiconductor quantum well structure. In the first mechanism, only quantum coherence induced by the resonant coupling of a strong control laser is considered. In the second mechanism, the decay coherence is taken into account under the condition where the control field is weak. In two different cases, optical bistability can be obtained through choosing appropriate physical parameters. Our studies show quantum coherence makes the optical nonlinear effect of the system become stronger, which takes an important role in the process of generating optical bistability. A semiconductor quantum well with flexibility and easy integration in design could potentially be exploited in real solid-state devices.

Chinese Physics BFeb 1, 20136 citations

Coherence and Quantum Optics

L. Mandeļ, E. Wolf

Springer eBooksJan 1, 197387 citations

Experimental control of the degree of non-classicality via quantum coherence

Andrea Smirne, Thomas Nitsche, Dario Egloff +6 more

Abstract The origin of non-classicality in physical systems and its connection to distinctly quantum features such as entanglement and coherence is a central question in quantum physics. This work analyses this question theoretically and experimentally, linking quantitatively non-classicality with quantum coherence. On the theoretical front, we show when the coherence of an observable is linearly related to the degree of violation of the Kolmogorov condition, which quantifies the deviation from any classical (non-invasive) explanation of the multi-time statistics. Experimentally, we probe this connection between coherence and non-classicality in a time-multiplexed optical quantum walk. We demonstrate exquisite control of quantum coherence of the walker by varying the degree of coherent superposition effected by the coin, and we show a concomitant variation in the degree of non-classicality of the walker statistics, which can be accessed directly by virtue of the unprecedented control on the measurement-induced effects obtained via fast programmable electro-optic modulators.Abstract The origin of non-classicality in physical systems and its connection to distinctly quantum features such as entanglement and coherence is a central question in quantum physics. This work analyses this question theoretically and experimentally, linking quantitatively non-classicality with quantum coherence. On the theoretical front, we show when the coherence of an observable is linearly related to the degree of violation of the Kolmogorov condition, which quantifies the deviation from any classical (non-invasive) explanation of the multi-time statistics. Experimentally, we probe this connection between coherence and non-classicality in a time-multiplexed optical quantum walk. We demonstrate exquisite control of quantum coherence of the walker by varying the degree of coherent superposition effected by the coin, and we show a concomitant variation in the degree of non-classicality of the walker statistics, which can be accessed directly by virtue of the unprecedented control on the measurement-induced effects obtained via fast programmable electro-optic modulators.

arXiv:1910.11830Quantum Science and TechnologyJun 25, 202013 citations

Coherence and Quantum Optics

T. Stewart McKechnie

Optica Acta International Journal of OpticsJun 1, 19764 citations

Experimental test of the trade-off relation for quantum coherence

Wei-Min Lv, Chao Zhang, Xiao‐Min Hu +6 more

As one of the most essential properties of quantum mechanics, quantum coherence is also considered a key physical resource which can be used to accomplish certain tasks of quantum information processing. Significant efforts are involved in the quantification of quantum coherence using measures such as the ${l}_{1}$ -norm and the relative entropy of coherence. The quantum coherence as a physical resource is usually defined with respect to a given basis, which also arouses an issue of interest concerning the variation of quantum coherence for a quantum state in different reference bases. In this paper, using an all optical setup, we experimentally investigate a trade-off relation between the coherence measures quantified by relative entropy of coherence in two noncommuting reference bases. Our result shows that the sum of quantum coherence under these bases is bounded in a region defined by its lower bound and upper bound.As one of the most essential properties of quantum mechanics, quantum coherence is also considered a key physical resource which can be used to accomplish certain tasks of quantum information processing. Significant efforts are involved in the quantification of quantum coherence using measures such as the ${l}_{1}$-norm and the relative entropy of coherence. The quantum coherence as a physical resource is usually defined with respect to a given basis, which also arouses an issue of interest concerning the variation of quantum coherence for a quantum state in different reference bases. In this paper, using an all optical setup, we experimentally investigate a trade-off relation between the coherence measures quantified by relative entropy of coherence in two noncommuting reference bases. Our result shows that the sum of quantum coherence under these bases is bounded in a region defined by its lower bound and upper bound.

Physical Review ADec 28, 201824 citations

{l}_{1}

-norm and the relative entropy of coherence. The quantum coherence as a physical resource is usually defined with respect to a given basis, which also arouses an issue of interest concerning the variation of quantum coherence for a quantum state in different reference bases. In this paper, using an all optical setup, we experimentally investigate a trade-off relation between the coherence measures quantified by relative entropy of coherence in two noncommuting reference bases. Our result shows that the sum of quantum coherence under these bases is bounded in a region defined by its lower bound and upper bound.