ProfileNathan attended Kenesserie Camp from 1990 until 2001. Despite its limited financial resources, Kenesserie was described by the Ontario Camping Association as having one of the most creative children's programs in the province. While on staff, Nathan was intimately involved with Kenesserie's program development and served as Program Director in 2001.
Nathan completed his undergraduate degree in Honours Physics at the University of Waterloo in 2005. While there, he designed and built components for x-ray diffraction experiments in the Waterloo Soft Matter research group, and later developed algorithms for quantum state purification at the Institute for Quantum Computing. He wrote his undergrad thesis on quantum mechanical heat engines under the direction of Lucien Hardy at the Perimeter Institute for Theoretical Physics.
He is now a doctoral candidate under the supervision of Barry Sanders at the University of Calgary. He collaborates with Aurelien de la Lande and Dennis Salahub at the Institute for Biocomplexity and Informatics, applying the concepts and mathematics of quantum information theory to the molecular engines that power all oxygen-breathing life as we know it.
When he isn't thinking about science, Nathan writes poetry, composes electronic music, bakes pies, practices yoga, and hollers madly from the roof of his garage.
In pursuit of knowledge, every day something is learned.
In pursuit of Tao, every day something is unlearned.
Less and less is done, until Wu Wei is achieved:
When nothing is done, nothing is left undone.
Quantum Transport in Molecular Biology
Coherent Control of Atomic Qubits
Quantum Thermodynamics
Foundations of PhysicsOutputs
Title | Category | Date | Authors |
Entanglement of group-II-like atoms with fast measurement for quantum information processing University of Calgary | Publication | 2008-01-01 | N. Babcock | Entangling identical bosons in optical tweezers via exchange interaction University of Calgary | Publication | 2008-05-01 | N. Babcock, R. Stock, M. G. Raizen, B. C. Sanders | Rapid control and measurement of qubits in atomic Yb and Sr University of Calgary | Presentation | 2006-05-24 | N. Babcock, R. Stock, B. C. Sanders, M. A. Dudarev, G. M. Raizen | Entangling neutral atoms with symmetrization-dependent dynamicsTrapped neutral atoms provide a promising medium in which to perform quantum computations since they have long decoherence times and can easily be interfaced with light for single-qubit operations and measurements. Despite these advantages, reliable methods for entangling and transporting atomic qubits must be devised before practical atomic quantum information processing devices can be realized. We propose a method for entangling a pair of indistinguishable neutral atoms stored in separated optical dipole traps. We model this trapping potential in one dimension as a pair of Gaussian wells that can be brought together for atoms to interact. The dynamics of this process depend on the symmetrization parameters of the initial state, and by choosing the correct interaction time a controlled-phase gate can be designed. Adiabatic separation guarantees that the atoms end up in opposite traps. We provide both adiabatic and time-dependent numerical simulations of the entangling process. Additionally, we consider a novel method for creating entangled qubits via selective excitation of atoms in such optical dipole traps. University of Calgary | Presentation | 2007-06-07 | N. Babcock, R. Stock, G. M. Raizen, B. C. Sanders | Entangling neutral atoms in optical dipole trapsTrapped neutral atoms are promising candidates for performing quantum computations since they have long decoherence times and can easily be interfaced with light for single-qubit operations and measurements. We propose a method for entangling a pair of indistinguishable neutral atoms stored in separated optical dipole traps. We model this trapping potential in one dimension as a pair of Gaussian wells that can be brought together for atoms to interact. The dynamics of this process depend on the symmetrizations of the atomic subsystems. By choosing the correct interaction time a controlled-phase gate can be designed. Adiabatic separation guarantees that the atoms end up in opposite traps. We provide both adiabatic and time-dependent numerical simulations of the entangling process. Additionally, we consider a novel method for creating entangled qubits via selective excitation of atoms in an optical dipole trap.
University of Calgary | Presentation | 2007-06-02 | N. Babcock, R. Stock, B. C. Sanders, G. M. Raizen | Bioelectric motors: bridging the gapA series of membrane-bound proteins called the cellular respiratory chain (or "electron transport chain") serves as the power system sustaining all known oxygen-breathing life on Earth. This system is essentially a chain of electric motors, powered by the flow of tunneling electrons. Thanks to the advent of sophisticated experimental and numerical techniques, biological molecules have become a particularly attractive medium in which to study quantum transport.
The bacterium Paracoccus denitrificans is believed to share a common ancestor with the modern mitochondrion (the "powerhouse of the cell"). I present numerical characterizations of molecular motion at an inter-protein electron transfer interface in the respiratory chain of Paracoccus denitrificans. I am motivated by a recent experiment in which anomalous electron transfer rates were measured for this tunneling step [Ma et al., Biochemistry 46, 11137 (2007)]. I argue that specific amino acids are likely to harness nearby water molecules to bridge the inter-protein gap, enhancing the tunneling rate. University of Calgary | Presentation | 2009-03-25 | N. Babcock, A. l. De, D. Salahub, B. C. Sanders | Quantum theory at MathCampQuantum Theory comes to Burning Man, Black Rock City, NV A three part lecture series introducing various topics in quantum theory
Part I: Quantization & Uncertainty - waves & particles - the ultraviolet catastrophe - Planck's quick & dirty fix - Einstein's courageous guess - operator algebras for fun & profit - bras, kets, & inner products - quantum bits - Fourier's transformation - sampling theory & the uncertainty principle
Part II: Spooky Action at a Distance - conceptual review (quantization & matrix algebra) - the superposition principle - measurement & wavefunction collapse - Hadamard's basis - entanglement & shared randomness - no superluminal signaling! - John Bell challenges Einstein's reality - hidden variable theories - gremlins & free will
Part III: Interpretation & Beyond - conceptual review (quantization & entanglement) - how to test Nature's spookiness (in a laboratory) - incomprehensible physics jargon - the measurement problem - the eerie magic of wavefunction collapse - the Orthodox interpretation (Don't ask, don't tell.) - the Many Worlds interpretation (No collapse, multiply me.) - the Statistical interpretation (Ain't no wavefunction anyhow.) - quantum consciousness? - synchronicity & human nature University of Calgary | Presentation | 2008-08-27 | N. Babcock | Quantum theory at MathCamp 2009Quantum Theory at Burning Man, Black Rock City, NV A three part lecture series introducing various topics in quantum theory
Tuesday: Quantization - Ultraviolet Catastrophe - Planck & Einstein - Young's Double Slit Experiment - Timmy falls down an infinitely deep well... - Eigenfunctions of the infinite square well!
Wednesday: Penetration of Classically Forbidden Regions - Poorly explained operators & stuff (explained poorly). - Timmy falls down a less-than-infinitely deep well... - How can something be where it's not? - Energy conservation and measurement in the Forbidden Region.
Thursday: Tunneling and Teleportation - Single Barrier Potential - Tunneling (Timmy plays a trick!) - Double Barrier Potential - Two wrongs can make a right! - Resonant Tunneling & Superexchange - Quantum Consciousness? - For real real (not for play play) quantum effects in biology. - Quantum Tunneling in Cellular Respiration University of Calgary | Presentation | 2009-09-01 | N. Babcock | Quantum theory at MoNo University of Calgary | Presentation | 2009-07-17 | N. Babcock | Quantum physics at MoNo University of Calgary | Presentation | 2010-07-17 | N. Babcock | A molecular breakwater enhances electron transfer between proteinsDoes natural selection optimize molecular biomachinery at the quantum level? We present statistical characterizations of molecular dynamics at an interprotein electron transfer (ET) interface. In simulations of the wild-type protein complex, we find that the most frequently occurring molecular configurations afford superior electronic coupling due to the consistent presence of a single water molecule hydrogen-bonded between the donor and acceptor sites. We attribute the persistence of this water bridge to a ``molecular breakwater'' composed of several hydrophobic residues surrounding the acceptor site. The breakwater supports the function of solvent-organizing residues by limiting the exchange of water molecules between the sterically constrained ET region and the surrounding bulk. When the breakwater is affected by a mutation, bulk solvent molecules disrupt the water bridge, resulting in reduced electronic coupling. These results suggest that protein surface residues may stabilize interprotein solvent dynamics to enable coherent ET along a single molecular pathway. University of Calgary | Presentation | 2011-03-23 | N. Babcock, A. l. De, J. Řezáč, B. C. Sanders, D. Salahub | Coherent & incoherent electron transfer in biological systemsIntermolecular electron transport is vital to the life of all respiring organisms (i.e., the vast majority of Earth's biomass). During electron transfer, any structures between the donor and acceptor molecules are collectively referred to as the "bridge." Interferences between multiple tunneling pathways through the bridge can enhance or reduce electronic coupling. A clear picture of decoherence due to dynamic bridge effects is therefore necessary to understand electron transport in biological systems. In respiring organisms, adenosine-5'-triphosphate (ATP) is recycled at a membrane-bound complex called the "electron transport chain," which in turn is powered by electricity produced from the oxidation of food (chemosynthesis) or the absorption of sunlight (photosynthesis). In this work, we examine a single bridging step in the electron transport chain of Paracoccus denitrificans. Recent experiments have shown this process to be extremely sensitive to the change of just a few atoms in the surrounding protein structure. We hypothesize that this reaction is mediated by a bridge of water molecules stabilized by nearby amino acid residues, effectively suppressing the decoherence of the through-water coupling term. We test this hypothesis using molecular mechanics and density functional theory to calculate the electronic coupling matrix elements for a variety of configurations. We believe the mathematical tools and intuition of quantum information theory will help provide deeper insight into the role of decoherence in this intriguing phenomenon. University of Calgary | Presentation | 2008-06-17 | N. Babcock, A. l. De, D. Salahub, B. C. Sanders | A molecular breakwater enhances electron transfer between proteins University of Calgary | Publication | 2011-03-01 | N. Babcock, A. l. De, J. Rezác, B. C. Sanders, D. Salahub | Correction: Surface residues dynamically organize water bridges to enhance electron transfer between proteins (PNAS, vol 107, pg 11799, 2010) University of Calgary | Publication | 2013-01-01 | A. d. Lande, N. Babcock, J. Řezáč, B. C. Sanders, D. Salahub | Rapid control and measurement of clock-state qubits in Yb and Sr for quantum information processing University of Calgary | Presentation | 2006-07-17 | R. Stock, N. Babcock, M. A. Dudarev, G. M. Raizen, B. C. Sanders | Electron superhighways and bridges in protein complexesDoes Natural Selection optimize biomachinery at the quantum level? Does quantum coherence play a role in biochemical electron transport? We show
that a particular redox protein complex is configured so that metastable water bridges act as "superhighways" for coherent electron transport between its constituent protein molecules. The bridge enables fast coherent electron transport across the gap instead of dooming the electron to slow thermal hopping through the interprotein medium. Although our study focuses on a particular protein complex
that has been frozen and characterized by crystallography, we conjecture that bridge-building is ubiquitous for redox processes.
University of Calgary | Presentation | 2009-06-19 | B. C. Sanders, N. Babcock, A. l. De, D. Salahub | Integrating out the quantum nature of electron transfer processes at the macromolecular scales University of Calgary | Presentation | 2012-10-08 | A. l. De, N. Babcock, B. C. Sanders, D. Salahub, E. H. El, C. Houée-Levin, B. Lévy, I. Demachy |
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