Final Report Summary - QUANTUM BIOTECH (QUANTUM PHENOMENA IN BIOLOGY: THEORY AND EXPERIMENTS TOWARDS NOVEL SOLAR ENERGY QUANTUM TECHNOLOGIES)
State-of-the-art
Nowadays, the alarming trends in global energy demand and the finite nature of conventional oil and natural gas reserves are unavoidably leading to the urgency of finding and timely developing new green energy systems. Recent experiments, based on ultra-fast spectroscopy techniques, have shown that electronic energy transfer in light-harvesting complexes, involved in one step of bacterial photosynthesis, occurs almost instantaneously (in the very short time scale of picoseconds) and very remarkably efficiently (nearly 100%), thanks to quantum physics mechanisms. In the last few years, this had led to a new challenging, exciting, young but very rapidly developing research field, i.e. quantum biology, focused on theoretical and experimental investigations of quantum effects in biology, paving also the way for new, more efficient, solar cells based on natural photosynthesis and quantum phenomena.
The main goal of this project is the theoretical and experimental investigation of the role of quantum effects in biological transport phenomena by studying theoretical models and designing new experimental schemes that are based on quantum optical networks, cold atom platforms, and ultra-fast spectroscopy for natural and artificial light-harvesting structures.
During the first 24 months of the project, the Researcher has mainly worked on the following three topics (towards objectives 1, 2, 3 and 4 of the project):
(i) Proposals of new optics-based spectroscopy experiments on biological molecules, assisted also by optimal control theory tools [F. Caruso et al., Phys. Rev. B 85, 125424 (2012), J. Cai et al., Phys. Rev. A 85, 040304(R) (2012), F. Caruso et al., Phys. Rev. A 85, 042331 (2012), S. Hoyer et al., New J. Phys. 16 , 045007 (2014)].
(ii) Quantum transport phenomena and entanglement measures with cold atoms in optical lattices and atom-chips [M. Cramer et al., Nat. Commun. 4, 2161 (2013), F. Schafer et al., Nature Commun. 5 , 3194 (2014), C. D’Errico et al., New. J. Phys. 15, 045007 (2013)].
(iii) Analysis of the role of noise, underlying geometry, and memory effects in transport of energy/information in open quantum systems and over complex (e.g. optical) networks, and
preliminary experimental characterization of optical simulators of transport mechanisms [F. Caruso, New. J. Phys. 16 , 055015 (2014), F. Caruso et al., Rev. Mod. Phys. 86 , 1203 (2014)].
Concerning (i), we have demonstrated theoretically that open-loop quantum optimal control techniques can provide efficient tools for the verification of various quantum coherent transport
mechanisms in natural and artificial light-harvesting complexes under realistic experimental conditions. They were also applied to optimize the magnetic sensitivity of the chemical compass, toward the design of a biomimetic weak magnetic field sensor. Finally, we have proposed a driven optical cavity quantum electrodynamics (QED) setup aimed at directly probing energy transport dynamics in photosynthetic biomolecules in terms of quantum optical phenomena.
As regards (ii), disorder, noise and interaction play a crucial role in the transport properties of real systems, but they are typically hard to control and study, both theoretically and experimentally, especially in the quantum case. For these reasons, we have explored a paradigmatic problem, the diffusion of a wavepacket, by employing ultra-cold atoms in a quasi-periodic lattice with controlled noise and tunable interaction. In addition, we have experimentally measured the presence of quantum coherence in many-body ultra-cold interacting bosons in optical lattices, by adopting recently developed approaches for the determination of rigorous lower entanglement bounds from readily accessible measurements. Finally, in the context of another atom physics experiment at LENS, we have demonstrated the role of engineered external noise and strong coupling in tailoring and protecting the coherent evolution of a quantum system.
Concerning (iii), we have exploited the formalism of quantum stochastic walks to investigate the capability to quickly and robustly transmit energy (or information) from two distant points in very large complex structures, remarkably assisted by external noise and quantum features as coherence. An optimal mixing of classical and quantum transport is, very surprisingly, universal for a large class of complex networks. Furthermore, spatial and temporal noise effects (as non-Markovian models) were also reviewed in the more general context of transfer of energy or quantum information and by means of the theoretical framework of open (i.e. non-unitary or interacting with external environment) quantum systems.
During the second 24 months of the project, Dr. Caruso has mainly worked on the following three topics (towards objectives 1, 2, 3, 4, and 5 of the project):
(iv) Understanding of the transport behavior of open quantum systems [Li et al., New J. Phys. 17 , 013057 (2015), S. Gherardini et al., in press in New J. Phys. (2016), F. Caruso et al., under review in Nature Communications (2016)].
(v) Observation of noise-assisted transport in an all-optical cavity-based network [S. Viciani et al., Phys. Rev. Lett. 115 , 083601 (2015), PRL Editors' Suggestion].
(vi) Significant enhancement of the energy transport in an intermediate quantum-classical regime in a tunable material consisting of a 3D chromophore network on an ordered biological virus template [H. Park, et al., Nature Materials, AOP doi:10.1038/nmat4448 (2015)].
Concerning (iv), we have shown a simple and intuitive explanation for the intriguing observation that optimally efficient networks are not purely quantum, but are assisted by some interaction with a ‘noisy’ classical environment. Indeed, we have demonstrated that the effect of classical noise is to sustain a broad momentum distribution, countering the depletion of high mobility terms which occurs as energy exits from the network. These results were also applied to the maze problem, that was also investigated experimentally by integrated waveguide arrays.
As regards (v), we have demonstrated the feasibility of an experimental setup of coupled cavities, only based on single-mode fiber optic components, which can efficiently reproduce, in agreement with theoretical models, the performance of transport networks for different conditions of interference, dephasing, and disorder. This has allowed us to show that the transport efficiency reaches a maximum when varying the external dephasing noise, i.e. a bell-like shape behavior that had been predicted only theoretically so far.
Concerning (vi), we have created a tunable material consisting of a connected chromophore network on an ordered biological (M31) virus template. In particular, using genetic engineering, we have established a link between the inter-chromophoric distances and emerging transport properties. The combination of spectroscopy measurements and dynamic modeling has enabled us to elucidate quantum coherent and classical incoherent energy transport at room temperature. Indeed, through genetic modifications, we have obtained a significant enhancement of exciton diffusion length of about 68% in an intermediate quantum-classical regime.
Transfer of knowledge
Here we describe the main activites organized by the Researcher to transfer his knowledge and expertise, acquired abroad in the internationally leading theoretical group on quantum physics of Prof. M.B. Plenio, strongly involved with a leading role in the vibrant, rapidly expanding, and cross-disciplinary field of research on “Quantum Effects in Biology”, since its inception in 2008.
At the level of the Host Institution, he has given at LENS several formal and informal seminars on different parts of this research project and, more importantly, he has organized an open access (free) and broad audience workshop on Quantum Transport in Light-Harvesting Bio-Nanostructures, at the Lecture Hall of the Physics Department of Florence University, in March 2013. As outreach activity, the Researcher has been selected as one of the three invited special guests to give a public talk on the research activity of this project, at a public meeting with the Italian President of the Chamber of Deputies, Mrs. Laura Boldrini, whose title was “Talents from the South to face the crisis”, in October 2013. Finally, Dr. Caruso has been the chair and main organiser of the International Conference on Quantum Effects in Biological Systems, QuEBS2015, that has been organized earlier by very prestigious institutions, as Harvard and UC Berkeley. Indeed, it has been for the first time in Italy, June 29-July 2, 2015, in the Hall of the Five Hundreds in Palazzo Vecchio and in Villa Bardini, Florence, organized by him, including 150 participants, 25 invited speakers, and around 70 contributions (quebs2015.weebly.com).
Nowadays, the alarming trends in global energy demand and the finite nature of conventional oil and natural gas reserves are unavoidably leading to the urgency of finding and timely developing new green energy systems. Recent experiments, based on ultra-fast spectroscopy techniques, have shown that electronic energy transfer in light-harvesting complexes, involved in one step of bacterial photosynthesis, occurs almost instantaneously (in the very short time scale of picoseconds) and very remarkably efficiently (nearly 100%), thanks to quantum physics mechanisms. In the last few years, this had led to a new challenging, exciting, young but very rapidly developing research field, i.e. quantum biology, focused on theoretical and experimental investigations of quantum effects in biology, paving also the way for new, more efficient, solar cells based on natural photosynthesis and quantum phenomena.
The main goal of this project is the theoretical and experimental investigation of the role of quantum effects in biological transport phenomena by studying theoretical models and designing new experimental schemes that are based on quantum optical networks, cold atom platforms, and ultra-fast spectroscopy for natural and artificial light-harvesting structures.
During the first 24 months of the project, the Researcher has mainly worked on the following three topics (towards objectives 1, 2, 3 and 4 of the project):
(i) Proposals of new optics-based spectroscopy experiments on biological molecules, assisted also by optimal control theory tools [F. Caruso et al., Phys. Rev. B 85, 125424 (2012), J. Cai et al., Phys. Rev. A 85, 040304(R) (2012), F. Caruso et al., Phys. Rev. A 85, 042331 (2012), S. Hoyer et al., New J. Phys. 16 , 045007 (2014)].
(ii) Quantum transport phenomena and entanglement measures with cold atoms in optical lattices and atom-chips [M. Cramer et al., Nat. Commun. 4, 2161 (2013), F. Schafer et al., Nature Commun. 5 , 3194 (2014), C. D’Errico et al., New. J. Phys. 15, 045007 (2013)].
(iii) Analysis of the role of noise, underlying geometry, and memory effects in transport of energy/information in open quantum systems and over complex (e.g. optical) networks, and
preliminary experimental characterization of optical simulators of transport mechanisms [F. Caruso, New. J. Phys. 16 , 055015 (2014), F. Caruso et al., Rev. Mod. Phys. 86 , 1203 (2014)].
Concerning (i), we have demonstrated theoretically that open-loop quantum optimal control techniques can provide efficient tools for the verification of various quantum coherent transport
mechanisms in natural and artificial light-harvesting complexes under realistic experimental conditions. They were also applied to optimize the magnetic sensitivity of the chemical compass, toward the design of a biomimetic weak magnetic field sensor. Finally, we have proposed a driven optical cavity quantum electrodynamics (QED) setup aimed at directly probing energy transport dynamics in photosynthetic biomolecules in terms of quantum optical phenomena.
As regards (ii), disorder, noise and interaction play a crucial role in the transport properties of real systems, but they are typically hard to control and study, both theoretically and experimentally, especially in the quantum case. For these reasons, we have explored a paradigmatic problem, the diffusion of a wavepacket, by employing ultra-cold atoms in a quasi-periodic lattice with controlled noise and tunable interaction. In addition, we have experimentally measured the presence of quantum coherence in many-body ultra-cold interacting bosons in optical lattices, by adopting recently developed approaches for the determination of rigorous lower entanglement bounds from readily accessible measurements. Finally, in the context of another atom physics experiment at LENS, we have demonstrated the role of engineered external noise and strong coupling in tailoring and protecting the coherent evolution of a quantum system.
Concerning (iii), we have exploited the formalism of quantum stochastic walks to investigate the capability to quickly and robustly transmit energy (or information) from two distant points in very large complex structures, remarkably assisted by external noise and quantum features as coherence. An optimal mixing of classical and quantum transport is, very surprisingly, universal for a large class of complex networks. Furthermore, spatial and temporal noise effects (as non-Markovian models) were also reviewed in the more general context of transfer of energy or quantum information and by means of the theoretical framework of open (i.e. non-unitary or interacting with external environment) quantum systems.
During the second 24 months of the project, Dr. Caruso has mainly worked on the following three topics (towards objectives 1, 2, 3, 4, and 5 of the project):
(iv) Understanding of the transport behavior of open quantum systems [Li et al., New J. Phys. 17 , 013057 (2015), S. Gherardini et al., in press in New J. Phys. (2016), F. Caruso et al., under review in Nature Communications (2016)].
(v) Observation of noise-assisted transport in an all-optical cavity-based network [S. Viciani et al., Phys. Rev. Lett. 115 , 083601 (2015), PRL Editors' Suggestion].
(vi) Significant enhancement of the energy transport in an intermediate quantum-classical regime in a tunable material consisting of a 3D chromophore network on an ordered biological virus template [H. Park, et al., Nature Materials, AOP doi:10.1038/nmat4448 (2015)].
Concerning (iv), we have shown a simple and intuitive explanation for the intriguing observation that optimally efficient networks are not purely quantum, but are assisted by some interaction with a ‘noisy’ classical environment. Indeed, we have demonstrated that the effect of classical noise is to sustain a broad momentum distribution, countering the depletion of high mobility terms which occurs as energy exits from the network. These results were also applied to the maze problem, that was also investigated experimentally by integrated waveguide arrays.
As regards (v), we have demonstrated the feasibility of an experimental setup of coupled cavities, only based on single-mode fiber optic components, which can efficiently reproduce, in agreement with theoretical models, the performance of transport networks for different conditions of interference, dephasing, and disorder. This has allowed us to show that the transport efficiency reaches a maximum when varying the external dephasing noise, i.e. a bell-like shape behavior that had been predicted only theoretically so far.
Concerning (vi), we have created a tunable material consisting of a connected chromophore network on an ordered biological (M31) virus template. In particular, using genetic engineering, we have established a link between the inter-chromophoric distances and emerging transport properties. The combination of spectroscopy measurements and dynamic modeling has enabled us to elucidate quantum coherent and classical incoherent energy transport at room temperature. Indeed, through genetic modifications, we have obtained a significant enhancement of exciton diffusion length of about 68% in an intermediate quantum-classical regime.
Transfer of knowledge
Here we describe the main activites organized by the Researcher to transfer his knowledge and expertise, acquired abroad in the internationally leading theoretical group on quantum physics of Prof. M.B. Plenio, strongly involved with a leading role in the vibrant, rapidly expanding, and cross-disciplinary field of research on “Quantum Effects in Biology”, since its inception in 2008.
At the level of the Host Institution, he has given at LENS several formal and informal seminars on different parts of this research project and, more importantly, he has organized an open access (free) and broad audience workshop on Quantum Transport in Light-Harvesting Bio-Nanostructures, at the Lecture Hall of the Physics Department of Florence University, in March 2013. As outreach activity, the Researcher has been selected as one of the three invited special guests to give a public talk on the research activity of this project, at a public meeting with the Italian President of the Chamber of Deputies, Mrs. Laura Boldrini, whose title was “Talents from the South to face the crisis”, in October 2013. Finally, Dr. Caruso has been the chair and main organiser of the International Conference on Quantum Effects in Biological Systems, QuEBS2015, that has been organized earlier by very prestigious institutions, as Harvard and UC Berkeley. Indeed, it has been for the first time in Italy, June 29-July 2, 2015, in the Hall of the Five Hundreds in Palazzo Vecchio and in Villa Bardini, Florence, organized by him, including 150 participants, 25 invited speakers, and around 70 contributions (quebs2015.weebly.com).