POSTDOCTORAL FELLOW - Chirality, Spin Coherence, and Entanglement in Quantum Biology
Arizona State University (ASU) and UCLA
As part of a new Keck center for “Chirality, Spin Coherence, and Entanglement in Quantum Biology” (UCLA – ASU – Northwestern), a postdoctoral position in theoretical molecular physics is available for the development of novel molecular quantum processing units, memories and interconnects that operate at high (>4 K) temperatures. The recent discovery of the CISS (chiral induced spin selectivity) effect has given rise to new opportunities for the creation of high temperature quantum information processing and transduction technology owing to the low dimensional helical properties of electron transport. The creation of operational communication and computational networks requires considerable theoretical and experimental developments ranging from the modeling of electron transport in molecular systems to the elucidation of the nature of chemical bonding between network components, as well as understanding the magnetic resonance properties of the electrons and nuclei and interaction of these components with external fields (optical, microwave or chemical signals).
This project aims to answer fundamental scientific questions such as, Why does nature rely on poorly conducting organic molecules as intermediates in essential electron-transfer processes?
We will explore the difference between metallic conduction and activated conduction subjected to important constraints such as: 1) low energies (to avoid damage) and 2) effects of temperature (from low to body or ambient temperatures) as well as regimes of insensitivity to temperature; 3) issues of stability. To make quantum networks viable we will explore possible solutions involving: 1) tunneling with constraints and 2) preservation of coherence over longer than typical tunneling distances. The role of spin in chirality has been largely ignored – to remedy this we will probe the special roles of spin coherence in quantum biology. This project will make use of well-defined chiral systems as working models; we will test the roles of spin and coherence with complementary experiments and with closely coupled theory. The building blocks to be explored include natural and unnatural enantiomers of DNA, switchable magnetic fields for all possible alignment combinations in experiments, fault-tolerant and built-in control experiments, low-energy probes for closest correlations with natural systems. Experiments will validate theory and be guided by it. The postdoc will model spin-polarized transport through chiral molecules, including magnetic fields and thermal effects. Modeling will address: 1) spin coherence and spin polarization in electron transfer and transport in open systems; 2) molecular magnetic response; 3) targeted molecular sequence and length. From this, we will learn more about: 1) the effects of magnetic field, temperature, molecular length, environment, and alignment of chirality and field; 2) interplay of CISS and intersystem crossing; 3) which molecules to measure experimentally (e.g., as tests of theory). CISS can be thought of as rich platform for the study of magnetic response, inter-system crossing and radical-pair interactions. Spin-orbit interactions couple spin and linear momentum in a non-trivial way, giving rise to exotic effects such as anomalous distance & temperature independence of conduction. The inclusion of spin changes everything; for example, the innocent view of spin dictates that the electron transfer rates and conductance should be multiplied by 2x yet CISS imposes symmetry constraints, breaks time-reversal and space-inversion symmetries, in a picture that includes both electric and magnetic polarizability.
The ideal candidate should have a Ph.D. in physics or related fields (engineering, chemistry, quantum science), a solid track record of accomplishments and publications in theoretical physics, such as condensed matter physics or molecular quantum electrodynamics and a strong interest in fundamental science. Knowledge of field theories and/or methods of effective-field theory is not required initially, but may be needed later in the project to assess issues of scalability. The postdoc would be expected to acquire such knowledge during the course of the project if the need arises. This project will require pencil-and-paper theory and may eventually require computational work (e.g., electronic structure calculations, modeling of spin polarized electron transport, thermal and tunneling effects and quantum statistics). Expertise in quantum computing or magnetic resonance is not required, however, the candidate would be expected to learn what’s needed – such as computing decoherence effects of a spin-bath system involving realistic molecular structures for the case of Markovian and non-Markovian dissipation; thus, a good command of optical, phonon, electronic and nuclear degrees of freedom, as well as their interactions, is needed. The goal of the project is to study the fundamental physics of the CISS effect in biological molecules, while exploring connections to and potential for quantum information at finite temperatures. The project is funded by the Keck Foundation and is officially a collaboration between UCLA, ASU and Northwestern University. Additional collaborations with leading groups in Mexico and Spain synergistically complement the team by offering additional theoretical and experimental possibilities. The postdoc will work at ASU in close collaboration with UCLA. Monthly meetings with the entire team of collaborators will be held to discuss progress. It is expected that the products of our theory efforts will lead to fruitful ideas for experiments that our collaborators may carry out.
Requirements:
Ph.D. degree in a relevant field [e.g. condensed matter, soft matter and molecular physics, or quantum science and/or related field(s)];
Work experience or knowledge of topology, low dimensional electron transport, electron-phonon and spin-orbit interactions is an asset;
Pencil-and-paper theory;
Computational physics skills are an asset;
Ability to work with a team, including experimentalists;
Excellent communication skills.
Location: The postdoc will be supervised jointly by Profs. Vladimiro Mujica (ASU) and Louis Bouchard (UCLA). Prof. Mujica is a professor in the School of Molecular Sciences at ASU. He is one of the founders of the new Quantum Institute at ASU. He is a pioneer in the chirality-induced spin selectivity effect and the theory of spin-polarized electron transport. Prof. Bouchard has expertise in magnetic resonance.
Application: Send CV with a list of publications, statement of interest, and names of 3 references to Profs. Louis Bouchard (lsbouchard@ucla.edu) and Vladimiro Mujica (vmujica@asu.edu). The position is open to everyone (US citizens, Permanent Residents as well as non-citizens) and will remain open until it is filled.
