Birgitta Whaley (Berkeley Quantum Computation) at a LASER http://www.scaruffi.com/leonardo/feb2015b.html
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1) Quantum mechanics plays a role in various biological processes like photosynthesis, bird navigation, smell, and ion channels. 2) Quantum biology has long been studied since the 1930s when quantum effects were first probed in biological structures. 3) Modern tools of quantum science allow unprecedented study of structure and dynamics across biological time and size scales, revealing quantum effects like coherence in light harvesting complexes involved in photosynthesis.
Birgitta Whaley (Berkeley Quantum Computation) at a LASER http://www.scaruffi.com/leonardo/feb2015b.html
- 1. What role does Quantum Mechanics play in Biology? K. Birgitta Whaley, UC Berkeley
- 2. Exploring the Quantum in Biology plants, bacteria: photosynthesis bird naviga5on animal smell ion channels brain…
- 3. Quantum vs Classical ? W. H. Zurek, Physics Today, Oct. 1991
- 4. • QM should apply to biology (life) Bohr, Jordan,… 1929 onwards • 1935 probed genetic structure and mutations with X-rays Quantum Biology has long roots: first quantum probe of biological structures and function, acknowledgement of need to understand detailed molecular structure of functional biological entities N. Timofeev-Resovsky (genetics) K. Zimmer (photobiology) M. Delbrück (quantum physics)
- 5. Developing tools for studying biological structure and function at unprecedented spatial and temporal resolution Can quantum coherence be relevant for biological function? Biological func5on across all 5me and size scales A. Vaziri B. HHMI/U. Vienna
- 6. • First Era: 1930 ‒ 1950s (b.L.) molecular structure and pathways, energetics, kinetics, stability ‒ quantum nature of molecular energy levels, energy barriers... (Schrödinger What is Life? 1943) • Second Era:1960s onward (a.L.) Quantum dynamical effects ‒ new generations of dynamical probes, new tools and innovation via quantum science and technology... DNA 1953
- 7. • Microscopic probes of living cells, cellular response, biochemical & electrical monitoring, biomolecule delivery… • Ultrafast spectroscopy, e.g., for quantum dynamics of electronic energy transfer in photosynthesis Quantum Biology: tools of quantum science and nanotechnology give new probes of structure and dynamics of biological systems NV centers: R. Walsworth, J. Wrachtrup, M. Lukin, H. Park, A. Jacoby.... Si nanorods offer cellular access: H. Park G. Fleming, G. Scholes, G. Engel, R. van Grondelle, N. van Hulst....
- 8. Photosynthesis The “light” reac5ons are rapid and efficient, >95% conversion of photons …Secondary electron transfer reac5ons, Water spliMng, Proton transport across thylakoid membrane, Reduc5on of NADP+, ATP synthesis… Charge separa5on Reac6on Center Blue-‐absorbing pigments Red-‐absorbing pigments Orange-‐absorbing pigments “Antenna” Light-‐harves5ng bacteria green plants
- 9. Photosystem II is the most sophis6cated nano machine on earth Pablo Picasso – House and Trees Paris, Winter 1908 140g of chlorophyll per tree Reac5on Center Light Harvester How many chlorophylls are there in Picasso’s Tree? 500 mg of primary electron donor chlorophylls
- 10. Photosynthe5c membrane of purple bacteria Energy travels over 15-‐30 nm paths in 1 ns excita5on energy is spread out over rough energy landscape Quantum effects in photosynthesis 5 nm Light Harvester Reac5on Center light harves5ng has near perfect efficiency experiments reveal wave-‐like ‘quantum coherent’ energy transfer Absorp5on Energy Conversion -‐ + Energy Storage ATP NADPH Sucrose • quantum coherence contributes ~10% to efficiency • natural systems are op5mal with respect to all parameters, no ar5ficial system is compete5ve • coherence enables robust uphill and long range transport
- 11. Does excitation hop or travel like a wave?
- 12. What is coherence? Incoherent waves All together now! Pedalling in step Coherent waves Rela%ve phases are stable in %me, space
- 13. Coherent addi5on of waves of different frequencies gives beats interference phenomenon
- 14. τ T Emission Frequency Excitation Frequency Fourier Transform with Respect to τ 2D Electronic Correlation Spectrum A 2D spectrum is a correlation map between the initial and final excitations and coherences The correlation depends on the processes occurring during time T Spectrally resolved, heterodyne detected photon echo
- 15. FMO (green sulfur bacteria): 2D fsec spectra Measured Points: 0, 10, 20, 30, 40, 50, 65, 80, 95, 110, 125, 140, 155, 170, 185, 200, 220, 240, 260, 280, 300, 330, 360, 390, 420, 450, 480, 510, 540, 570, 600, 630, 660fs Fleming et al. 2007
- 16. Electronic entanglement | ⇥ |g⇥1|e⇥2 + |e⇥1|g⇥2 Site 1 Site 2 Non-‐local quantum correla5ons between molecular electronic states Schrödinger 1935: entanglement (Verschränkung) is “the characteris6c trait of quantum mechanics”
- 17. 17 Entanglement analog with ambiguous cube: perceive orientational correlations between boxes
- 18. All coherence experiments to date show quantum beating in a single complex – Is quantum coherence relevant to long range energy transfer? Photosystem II super-complex, courtesy of Roberta Croce • Is coherence transmitted between complexes? • If so, why? How might it help photosynthetic function? Hoyer et al. PRE (2012) • coherence is transmitted • enables unidirectional transport • enables uphill transport
- 19. Photosynthesis: what next? • fundamental understanding of quantum effects in efficient energy conversion for life, role in biology • reengineer photosynthesis - design of artificial devices for effective ‘quantum’ conversion of sunlight into chemical energy without competing biological constraints • lessons for design of robust and sensitive quantum devices an “evolved” natural quantum processor? design rules for robust quantum devices and efficient transduction of solar energy?
- 20. Elysia chlorotica captures chloroplasts from algae and store these in body, never need to eat again (for 9-11 months of life)…. Green sea slug