Quantum Information

I'm interested in understanding how the structure of molecules or materials affects their behavior. To understand this, I develop methods to model these materials properties more accurately, and apply them to materials that are interesting to me and important to the nation.

I'm currently interested in quantum computing. Can we build a quantum computer, and, if so, what would such a device be used for? I'm currently working with a group of researchers at Sandia to answer some of these questions. We're focusing on solid-state qubits in Silicon, using either electrostatically gated quantum dots, or implanted donor devices. We're interested in understand the requirements to make few electron quantum dots, and, given such dots, what their operations and errors will look like, and how to move qubits defined in such dots around in different architectures.

We have recently developed the QCAD (quantum dot computer aided design) program, which is a finite element code built atop the Trilinos rapid application development library Albany. The code enables sophisticated 3D semiconductor quantum structures to be modeled to determine how structural changes in the devices lead to different quantum device properties. The code also uses Dakota optimization library to determine optimal voltages to obtain few electron dot behavior.

Older Topics

Batteries

Electric, hybrid-electric, and plugin-hybrid-electric vehicles have been proposed as a panacea for many aspects of US energy woes. However, the cost, efficiency, reliability, and safety of these vehicles depends largely on the batteries they use.

In a past project, we considered safety aspects of transportation batteries. Thermal runaway is a known problem in Li-ion batteries, and Sandia has a particularly good laboratory to evaluate various aspects of battery safety. We're interested in developing an analogous modeling component, allowing materials to be rapidly tested for safety, in some cases even before the materials have been synthesized.

Catalysis

Alchemists looked at methods to transform lead into gold, and, in much the same spirit, chemists who study catalysis look at how a less expensive or important molecule can be transformed into a more expensive or more important molecule. I've long been interested in how modeling can help understand the performance of existing catalysts, as well as design new, more effective catalysts.

Combustion and Detonation

Energetic and high explosive materials perform some of the most spectacular chemical reactions known. In the past, I have investigated the reaction pathways of nitramine-based high explosives to understand how the materials work, how reliable and safe they are, and how we would expect them to degrade with age.

Method Development

I am the lead of the PyQuante project that implements quantum chemistry algorithms in the Python programming language to make them easier to learn, understand, and improve.

Many of the phenomena I've described above involve too many atoms or occur for too much time to describe purely with quantum chemical methods. Thus, my work of late has increasingly been interested with developing techniques in multiscale modeling to coarse-grain information from atomistic techniques so that it might faithfully be represented in mesoscale and continuum techniques.

My graduate work developed faster algorithms for two-electron integrals in electronic structure algorithms using pseudospectral approaches, as well as faster convergence techniques, work that is currently released in Schrodinger's Jaguar program. As a postdoc, I investigated QM/MM methods for enzyme catalysis. I have also considered some improved methods for QMC simulations.

Journal Articles

  1. Albany: A Component-Based Partial Differential Equation Code Built on Trilinos. Andrew G. Salinger, Roger P. Pawlowski, Eric T. Phipps, Roscoe A. Bartlett, Glen A. hansen, Irina Kalashnikova, Jakob T. Ostien, Waiching Sun, Quishi Chen, Alejandro Mota, Richard P. Muller, Erik Nielsen, Xujiao Gao. Submitted, ACM TOMS.

  2. Efficient self-consistent quantum transport simulator for quantum devices. X. Gao, D. Mamaluy, E. Nielsen, R. W. Young, A. Shirkhorshidian, M. P. Lilly, N. C. Bishop, M. S. Carroll, and R. P. Muller. Journal of Applied Physics, 115, 133707 (2014). Arxiv 1403.7564.

  3. QCAD Simulation and Optimization of Semiconductor Double Quantum Dots. E Nielsen, X Gao, I Kalashnikova, R P Muller, A G Salinger, and R W Young. SAND Report, 2013.

  4. Charge-sensed Pauli blockade in a MOS lateral double quantum dot. Khoi. T. Nguyen, Michael. P. Lilly, Erik Nielsen, Nathan Bishop, Rajib Rahman, Ralph Young, Joel Wendt, Jason Dominguez, Tammy Pluym, Jeffery Stevens, Tzu-Ming Lu, Richard Muller, Malcolm. S. Carroll. Nano Letters, 2013.

  5. QCAD Simulation and Optimization of Semiconductor Quantum Dots. X. Gao, E. Nielsen,R. P. Muller, R. W. Young, A. G. Salinger, N. C. Bishop, M. Lilly, and M. S. Carroll. Journal of Applied Physics, 114, 164302 (2013). Arxiv 1403.7561.

  6. Modelling challenges for battery materials and electrical energy storage. Richard P. Muller and Peter A. Schultz. Modeling and Simulation in Materials Science and Engineering, 21, 070301 (2013).

  7. Phase field model of solid electrolyte interphase formation in Li-ion batteries. Jie Deng, Gregory J. Wagner, and Richard P. Muller. Journal of the Electrochemical Society 160, A487 (2013).

  8. A many-electron tight binding method for the analysis of quantum dot systems. Erik Nielsen, Rajib Rahman, Richard P. Muller. Journal of Applied Physics 112, 114304 (2012). Arxiv 1202.4931.

  9. Modeling Thermal Abuse in Transportation Batteries Richard P. Muller, Randall T Cygan, Jie Deng, Amalie L Frischknecht, John C Hewson, Harry K Moffat, Craig M Tenney, Peter A Schultz, Gregory J Wagner. SAND Report, SAND2012-7816, September, 2012.

  10. Simulation of Abuse Behavior of Lithium-Ion Batteries. Robert Spotnitz and Richard Muller. Interface, 21, 57 (2012).

  11. Phase field model of solid electrolyte interphase formation in Li-ion batteries. Jie Deng, Gregory J. Wagner, and Richard P. Muller. MRS Proceedings, 1278, 1440 (2012).

  12. The QCAD Framework for Quantum Device Modeling. X. Gao, E. Nielsen, R. P. Muller, R. W. Young, A. G. Salinger, N. C. Bishop, and M. S. Carroll. International Workshop on Computational Electronics Proceedings, 15, 1, (2012).

  13. Voltage controlled exchange energies of a two electron silicon double quantum dot with and without charge defects in the dielectric. Rajib Rahman, Erik Nielsen, Richard P. Muller, Malcolm S. Carroll. Physical Review B, 85, 125423 (2012). Arxiv 1112.4025

  14. Configuration interaction calculations of the controlled phase gate in double quantum dot qubits. Erik Nielsen, Richard P. Muller, Malcolm S. Carroll. Physical Review B, 85, 35319 (2012). Arxiv 1106.1441

  15. Coherent electron transport by adiabatic passage in an imperfect donor chain. Rajib Rahman, Richard P. Muller, James E. Levy, Malcolm S. Carroll, Gerhard Klimeck, Andrew D. Greentree, and Lloyd C. L. Hollenberg. Physical Review B, 82, 155315 (2010). Arxiv 1008.1494

  16. Implications of Simultaneous Requirements for Low Noise Exchange Gates in Double Quantum Dots. Erik Nielsen, Ralph W. Young, Richard P. Muller, M. S. Carroll. Physical Review B, 82, 075319 (2010). Arxiv 0909.0047

  17. Calculation of chemical reaction energies using the AM05 density functional. Richard P. Muller, Ann E. Mattsson, Curtis L. Janssen. Journal of Computational Chemistry, 31, 1860-1863 (2010). Arxiv

  18. Enhancement mode double top gated MOS nanostructures with tunable lateral geometry. E.P. Nordberg, G.A. Ten Eyck, H.L. Stalford, R.P. Muller, R.W. Young, K. Eng, L.A. Tracy, K.D. Childs, J.R. Wendt, R.K. Grubbs, J. Stevens, M.P. Lilly, M.A. Eriksson, M.S. Carroll. Physical Review B, 80, 115331 (2009). Arxiv 0906.3748.

  19. Atomistic simulations of adiabatic coherent electron transport in triple donor systems. Rajib Rahman, Seung H. Park, Jared H. Cole, Andrew D. Greentree, Richard P. Muller, Gerhard Klimeck, Lloyd C. L. Hollenberg. Physical Review B, 80, 35302 (2009). Arxiv 0903.1142

  20. Hydrogenolysis of Palladium(II) Hydroxide and Methoxide Pincer Complexes. Gregory R. Fulmer, Richard P. Muller, Richard A. Kemp, and Karen I. Goldberg. Journal of the American Chemical Society, 131, 1346 (2009).

  21. Manager-worker-based model for the parallelization of quantum Monte Carlo on heterogeneous and homogeneous networks. Michael T. Feldmann, Julian C. Cummings, David R. Kent IV, Richard P. Muller, William A. Goddard III. Journal of Computational Chemistry, 29, 8-16 (2007).

  22. Efficient algorithm for on the fly error analysis of local or distributed serially correlated data. David R. Kent IV, Richard P. Muller, Amos G. Anderson, William A. Goddard III, Michael T. Feldmann. Journal of Computational Chemistry, 28, 2309-2316 (2007).

  23. Mechanism of Direct Molecular Oxygen Insertion in a Palladium (II) Hydride Bond. Jason M. Keith, Richard P. Muller, Richard A. Kemp, Karen I. Goldberg, William A. Goddard, III, and Jonas Oxgaard. Inorganic Chemistry. 45, 9631 (2006).

  24. Optimized Effective Potential from a Correlated Wave Function: OEP-GVB. Richard P. Muller and Michael P. Desjarlais. Journal of Chemical Physics. 125, 54101 (2006).

  25. Alkylation of phenol: A mechanistic view. Qisheng Ma, Deb Chakraborty, Francesco Faglioni, Richard P. Muller, William. A. Goddard, III, Thomas Harris, Curt Campbell, and Yongchun Tang. Journal of Physical Chemistry A. 110, 2246 (2006).

  26. A candidate LiBH4 for hydrogen storage: crystal structures and reaction mechanisms of intermediate phases. Jeung Ku Kang, SY Kim, YS Han, Richard P. Muller, and William A. Goddard, III. Applied Physics Letters. 87, 111904 (2005).

  27. An extended hybrid density functional (X3LYP) with improved descriptions of nonbond interactions and thermodynamic properties of molecular systems. Xin Xu, Qingsong Zhang, Richard P. Muller, and William A. Goddard, III. Journal of Chemical Physics. 122, 14105 (2005).

  28. Mechanism of the Stoddart-Heath Bistable Rotaxane Molecular Switch. Weiqiao Deng, Richard P. Muller, and William A. Goddard, III. Journal of the American Chemical Society, 126, 13562 (2004).

  29. Hydrogen storage in LiAlH4: Predictions of the crystal structures and reaction mechanisms of intermediate phases from quantum mechanics. Jeung Ku Kang, Jai Young Li, Richard P. Muller, and William A. Goddard, III. Journal of Chemical Physics, 121, 10623 (2004).

  30. The synthesis of symmetrical bis-1,2,5-thiadiazole ligands. Dean M. Philipp, Richard P. Muller, William A. Goddard, III, Khalil A. Abboud, Michael J. Mullins, R. Vernon Snelgrove, and Phillip S. Athey. Tetrahedron Letters. 45, 5441 (2004).

  31. Evidence of O-Atom Exchange in the O (1D) + N2O Reaction as the Source of Mass-Independent Fractionation in Atmospheric N2O. Yuk L. Yung, Mao-Chiang Liang, Geoffrey A. Blake, Richard P. Muller, and Charles E. Miller. Geophysical Research Letters, 31, L19106 (2004).

  32. Mechanism of Homogeneous Ir(III) Catalyzed Regioselective Arylation of Olefins. Jonas Oxgaard, Richard P. Muller, William A. Goddard, III, and Roy A. Periana. Journal of the American Chemical Society, 126, 352 (2004).

  33. Meccano on the Nanoscale: A Blueprint for Making the World's Smallest Devices. Amar H. Flood, Robert J. A. Ramirez, Wei-Qiao Deng, Richard P. Muller, William A. Goddard, III, and J. Frasier Stoddard. Australian Journal of Chemistry, 57, 301 (2004).

  34. Internal Lewis Acid Single Site Catalyst Family for Polymerization of Polar Monomers. Dean M. Phillipp, Richard P. Muller, and William A. Goddard, III. US Patent # 6,777,510 B1, awarded August 17, 2004.

  35. Chemisorption of Atomic Oxygen on Pt (111) from DFT Studies of Pt Clusters. Timo Jacob, Richard P. Muller, and William A. Goddard, III. Journal of Physical Chemistry B, 107, 9465 (2003).

  36. Computing Approximate Eigenpairs of Symmetric Block Tridiagonal Matrices. Wilfried Gansterer, Robert C. Ward, Richard P. Muller, and William A. Goddard, III. SIAM Journal on Scientific Computing, 25, 65 (2003).

  37. Quantum Mechanical-Rapid Prototyping Applied to Methane Activation. Richard P. Muller, Dean M. Philipp, and William A. Goddard, III. Topics in Catalysis, 23, 81 (2003).

  38. Application of Lightweight Threading Techniques to Computational Chemistry. John Thornley, Richard P. Muller, Daniel T. Mainz, Tahir Cagin, and William A. Goddard, III. Journal of Computer Aided Materials Design, 8 (2-3), 173-184 (2002).

  39. A Detailed Reaction Model for the Detonation of Nitramines: RDX and HMX. Debashis Chakraborty, Richard P. Muller, Siddharth Dasgupta, and William A. Goddard, III. Journal of Computer Aided Materials Design, 8 (2-3), 203-212 (2002).

  40. Computational Insights on the Challenges of Polymerizing Polar Monomers. Dean Philipp, Richard P. Muller, William A. Goddard, III, Joey Storer, Mark McAdon, and Mike Mullins. Journal of the American Chemical Society, 124 (34), 10198-10210 (2002).

  41. Copolymerization Studies of Vinyl Chloride and Vinyl Acetate with Ethylene Using a Transition-Metal Catalyst. Harold W. Boone, Phillip S. Athey, Michael J. Mullins, Dean Philipp, Richard Muller, and William A. Goddard, III. Journal of the American Chemical Society, 124 (30), 8790 - 8791 (2002).

  42. An Extension of the Divide-and-Conquer Method for a Class of Symmetric Block-Tridiagonal Eigenproblems. Wilfried N. Gansterer, Robert C. Ward, and Richard P. Muller. ACM Transactions on Mathematical Software. 28 (1), 45-58 (2002).

  43. An NMR and QM Investigation of Tetrahydrofuran Solvent Effects on the Conformational Equilibria of 1,4-Butanedioic Acid and its Salts. David R. Kent, IV, Krag A. Petterson, Francoise Gregoire, Ethan Snyder-Frey, Linda J. Hanely, Richard P. Muller, William A. Goddard, III, and John D. Roberts. Journal of the American Chemical Society, 124 (16), 4418-4486 (2002).

  44. The Gas Phase Reaction of Singlet Dioxygen with Water, a Water Catalyzed Reaction. Xin Xu, Richard P. Muller, William A. Goddard, III. Proceedings of the National Academy of Sciences, 99 (6), 3376-3381 (2002).

  45. Valence Bond Theory. Richard P. Muller and William A. Goddard, III. Encyclopedia of Physical Science and Chemistry. Third Edition. Robert A. Meyers, ed. Academic Press, 2002.

  46. Gas Phase and Surface Kinetic Processes in Polycrystalline Silicon Hot-wire Chemical Vapor Deposition. Jason K. Holt, M. Switek, David G. Goodwin, Richard P. Muller, William A. Goddard, III, and Harry A. Atwater. Thin Solid Films, 395, 29 (2001).

  47. Si + SiH4 Reactions and Implications for Hot-Wire CVD of a-Si:H. Computational Studies. Richard P. Muller, William A. Goddard, III, Jason K. Holt, and David G. Goodwin. Material Research Society Symposium Proceedings, 609, A6.1.1 (2001).

  48. The Mechanism for Unimolecular Decomposition of HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocine); An Ab Initio Study. Debashis Chakraborty, Richard P. Muller, Siddharth Dasgupta, and William A. Goddard, III. Journal of Physical Chemistry A, 105(8), 1302-1314 (2001).

  49. The Mechanism for Unimolecular Decomposition of RDX (1,3,5-trinitro-1,3,5-triazine); An Ab Initio Study. Debashis Chakraborty, Richard P. Muller, Siddharth Dasgupta, and William A. Goddard, III. Journal of Physical Chemistry A, 104(11), 2261-2272 (2000).

  50. Hybrid ab Initio Quantum Mechanics/Molecular Mechanics Calculations of Free Energy Surfaces for Enzymatic Reactions: The Nucleophilic Attack in Subtilisin. J. Bentzien, R. P. Muller, J. Florian, and A. Warshel. Journal of Physical Chemistry B, 102, 2293-2301 (1998).

  51. Semiempirical and ab initio modeling of chemical processes: From aqueous solution to enzymes. Richard P. Muller, Jan Florian, and Arieh Warshel. NATO Symposium Series: Biomolecular Structure and Dynamics: Recent Experimental and Theoretical Advances. G. Vergoten, ed.

  52. Calculations of chemical processes in solution by density functional and other quantum mechanical techniques. Richard P. Muller, Tomek Wesolowski, and Arieh Warshel. Density Functional Methods in Chemistry and Materials Science, M. Springborg, ed. John Wiley and Sons, New York, 1997.

  53. Ab initio calculations of free energy barriers for proton transfer in FHF- in solution. Richard P. Muller and Arieh Warshel. Pacific Syposium for Biocomputing 1996 L. Hunter and T. Klein, eds. World Scientific Press, Singapore, 1996, p. 524.

  54. Ab Initio Frozen Density Functional Calculations of Proton Transfer Reactions in Solution. Tomasz A. Wesolowski, Richard P. Muller, and Arieh Warshel. Journal of Physical Chemistry, 100, 15444 (1996).

  55. Ab Initio Calculations of Free Energy Barriers for Chemical Reactions in Solution. Richard P. Muller and Arieh Warshel. Journal of Physical Chemistry, 99 (49), 17516 (1995).

  56. Development and Optimization of Quantum Chemical Techniques for Application to Large Molecules. Richard P. Muller, Graduate Dissertation, California Institute of Technology, 1994.

  57. Rule-Based Trial Functions for Generalized Valence Bond Theory. Jean-Marc Langlois, Terumasa Yamasaki, Richard P. Muller, and William A. Goddard, III. Journal of Physical Chemistry, 98, 13498 (1994).

  58. A Generalized Direct Inversion in the Iterative Subspace Approach for Generalized Valence Bond Wave Functions: GVB-DIIS. Richard P. Muller, Jean-Marc Langlois, Murco N. Ringnalda, Richard A. Friesner, and William A. Goddard, III. Journal of Chemical Physics, 100, 1226 (1994).

  59. Pseudospectral Generalized Valence Bond (PS-GVB) Calculations: Application to Methylene, Ethylene, and Silylene. Jean-Marc Langlois, Richard P. Muller, Terry R. Coley, William A. Goddard, III, Murco N. Ringnalda, Yongdo Won, and Richard A. Friesner. Journal of Chemical Physics, 92, 7488 (1991).

  60. A Model for Impulsive Mode-Mode Energy Transfer in Highly Vibrationally Excited Molecules. Richard P. Muller, John S. Hutchinson, and Thomas A. Holme. Journal of Chemical Physics, 90, 4582 (1989).

iPython Notebooks

  1. A Crash Course in Python for Scientists
  2. PyQuante2 Overview
  3. Sympy Quantum Circuit Plotting
  4. SVG graphics in IPython notebooks
  5. Learning Quantum Chemistry with PyQuante: Coming Soon!
  6. Tensor Operations in Numpy: Using tensordot and einsum: Someday/Maybe