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2 - Open quantum system approaches to biological systems
- from Part I - Introduction
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- By Alireza Shabani, University of California, Masoud Mohseni, Google, Seogjoo Jang, University of New York, Akihito Ishizaki, University of California Berkeley, Martin Plenio, Universität Ulm, Patrick Rebentrost, Harvard University, Alan Aspuru-Guzik, Harvard University, Jianshu Cao, Massachusetts Institute of Technology, Seth Lloyd, Massachusetts Institute of Technology, Robert Silbey, Massachusetts Institute of Technology
- Edited by Masoud Mohseni, Yasser Omar, Gregory S. Engel, University of Chicago, Martin B. Plenio, Universität Ulm, Germany
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- Book:
- Quantum Effects in Biology
- Published online:
- 05 August 2014
- Print publication:
- 07 August 2014, pp 14-52
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- Chapter
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Summary
Quantum biology, as introduced in the previous chapter, mainly studies the dynamical influence of quantum effects in biological systems. In processes such as exciton transport in photosynthetic complexes, radical pair spin dynamics in magnetoreception, and photo-induced retinal isomerization in the rhodopsin protein, a quantum description is a necessity rather than an option. The quantum modelling of biological processes is not limited to solving the Schrödinger equation for an isolated molecular structure. Natural systems are open to the exchange of particles, energy or information with their surrounding environments that often have complex structures. Therefore the theory of open quantum systems plays a key role in dynamical modelling of quantum-biological systems. Research in quantum biology and open quantum system theory have found a bilateral relationship. Quantum biology employs open quantum system methods to a great extent while serving as a new paradigm for development of advanced formalisms for non-equilibrium biological processes.
In this chapter, we overview the basic concepts of quantum mechanics and approaches to open quantum system (or decoherence) dynamics. Here, we do not intend to discuss all aspects of about a century-old theory of open quantum systems that dates back to the original work of Paul Dirac on atomic radiative emission and absorption (Dirac, 1927). Instead, we mainly focus on the integro-differential equations that are commonly used for modelling quantum-biological systems. Interested readers can learn more about open quantum systems in various books and review articles in both physics and chemistry literature, including the references (Kraus, 1983; Breuer and Petruccione, 2002; Kubo et al., 2003; Weiss, 2008; May and Kühn, 2011).
Materials and Techniques of Thai Painting
- Katherine Eremin, Jens Stenger, Narayan Khandekar, Jo Fan Huang, Theodore Betley, Alan Aspuru-Guzik, Leslie Vogt, Ivan Kassal, Scott Speakman
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- Journal:
- MRS Online Proceedings Library Archive / Volume 1047 / 2007
- Published online by Cambridge University Press:
- 01 February 2011, 1047-Y06-04
- Print publication:
- 2007
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- Article
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The materials and techniques employed in 18th to 20th century art works from Thailand have received little attention compared to those of other Asian countries, most notably China and Japan. A multi-disciplinary study of Thai manuscripts and banner paintings aims to characterize the materials used, inorganic and organic pigments and binders, and the painting techniques employed. Samples from these works have been analyzed by a range of techniques, including x-ray flourescence (XRF), Raman spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive microanalysis (SEM-EDS). The results suggest a change in palette from the 18th to 20th century due to the introduction of imported pigments, most notably emerald green, Prussian blue and chrome yellow, during the 19th and early 20th century. The analyses show that the green pigment used on most 18th century manuscripts is an organic copper salt, a hydrated copper citrate, which has not previously been identified on art works. The occurrence of this on a number of different art works suggests deliberate manufacture of this unusual pigment. The color of the copper citrates differs depending on their hydration state and they are easily dehydrated and re-hydrated. This suggests some alteration of the original manuscript pigments might be expected, raising questions as to the original color of the pigment and whether the visual appearance has altered with time. In order to assess this, the pigments found on the art works must be fully characterized and any variations identified. The study includes laboratory based sythesis with pure reagents and synthesis following a recipe for refinement of verdigris given in a 17th century Venetian manuscript.