Memory effects in quantum biology: A mechanism for delaying quantum decoherence in cells?
Quantum effects and biological systems seem to be at odds with each other. Typically quantum effects are confined to very specific experimental conditions characterized by low temperatures and little interaction with the environment. In contrast biological systems are naturally warm, and strongly coupled with their own environment. However, it has recently emerged that quantum phenomena may be at the bases of a number of biological processes, such as photosynthesis, avian magnetoreception, and tunnelling processes in enzyme catalysis (see  for a review). In these systems, quantum coherence and entanglement are expected to be sustained for long times. Evidence has been collected that this is indeed the case for instance in photosynthesis .
The aim of this project is address theoretically the mechanisms that can contribute to sustain long-lived coherence in biological systems. In particular we aim to establishing a connection between decoherence times and non-Markov dynamics within the cell.
By using the theory of open quantum systems , we will test the hypothesis that the particular cellular environment might produce fluctuations (noise) with memory effects capable of increasing decoherence times . Different types of environmental noise will be analysed, both with and without memory, and the corresponding quantum master equations will be derived. The analysis will be carried out both analytically and numerically by using the influence functional formalism to characterize the dynamics of the reduced density matrix of the system. Decoherence times will be estimated in different non-Markov scenarios, and the relevance of memory in sustaining coherence in the cell assessed.
The student will learn about the theory of open quantum systems coupled to noise and its relevance to describe quantum phenomena in biological systems. A solid theoretical physics background is required.
Interested candidates should apply through the university website. Applicants should have a MS degree or first class degree in Physics or Mathematics, with solid knowledge of quantum mechanics and statistical mechanics. Even though previous knowledge in Biology is not required, a keen interest in the biological aspects of the project is desirable.
 N. Lambert et al., Quantum Biology, Nature Physics 9, 10-18 (2013).
 G. Panitchayangkoon et al., Long-lived quantum coherence in photosynthetic complexes at physiological temperature, PNAS 107, 12766-12770 (2010).
 W.T. Strunz, Decoherence in Quantum Physics, in “Coherent Evolution in Noisy Environments”, Eds. A. Buchleitner and K. Hornberger, Lecture Notes in Physics 611 (2002), chapter 5.
 A.W.Chin, S.F. Huelga and M.B. Plenio, Coherence and decoherence in biological systems: principles of noise-assisted transport and the origin of long-lived coherences, Phil. Trans. R. Soc. A 370, 3638-3657 (2012).