Electronic Structure Calculations (1)

Electronic Structure Calculations (1)

Near-term QC applications in industry Florian Neukart Volkswagen Group, Region Americas REQUIRED DEFINITION: USEFUL QUANTUM SUPREMACY Quantum supremacy: proof that quantum computing can perform a particular calculation that’s beyond the reach of any conventional computer. For the universal quantum computer and certain problems, this is supposed to be achieved with ~50 logical qubits. Universal quantum computers will also allow for the simulation of quantum particles, which is required for solving particular materials optimization problems involving large-scale quantum behavior. We prefer to talk about useful quantum supremacy, because only when we solve real-world problems, it makes sense for VW. 2 QUANTUM-ASSISTED ALGORITHMS Currently, certain hardware constraints are Type of algorithm given: • Up to 50 physical qubits for universal quantum classical quantum computers by the end of 2017/ early 2018 • ~2.000 qubits on quantum annealing systems CC CQ classical Most promising right now: • Quantum-assisted machine learning Type of data • Augmentation of deep learning, reinforcement QC QQ learning, optimization algorithms and sampling quantum • Quantum simulation § First letter: system under study is classical or quantum § Second letter: classical or quantum information processing device is used 3 WHAT‘S HAPPENING AT VW (1) Quantum annealing – With classical computers, some things we’ve done so far many of the most complex § Traffic flow optimization Materials problems can’t be solved. simulation § Reinforcement learning (i.e. financial market prediction, self-driving vehicle) § Finite elements § Machine learning (i.e. neural networks, NNMF) § Clustering (i.e. IT threat detection) § Vehicle price prediction Traffic flow optimization § Vehicle weight minimization Finite elements design Reinforcement4 learning Clustering WHAT‘S HAPPENING AT VW (2) Gate model – we are working on § Optimization (i.e. enhancing traffic flow optimization) § Machine learning (i.e. qantum neural networks, financial market analysis) § Simulation for possible discovery of new materials Materials (i.e. battery materials) simulation Additional results: § 5 academic R&D partnerships, mostly pro bono § Commercial partnerships with Google, D-Wave § Presentations received at 9 conferences § Publications pending in leading scientific journals 5 TRAFFIC FLOW OPTIMIZATION AND ACTUAL STATUS Full publication and description at https://www.frontiersin.org/articles/10.3389/fict.2017.00029/full Why quantum? • Recalculation happens almost instantaneously. • What we achieve: maximization of flux at any time. Actual status and next steps • Electrify America – optimization of routes under consideration of charging pillars. • Include additional optimization targets, and ideally work together with cities. • Reduction of accidents, prediction and avoidance of „danger zones“ (insurance?), reduction of emissions. 6 QUANTUM-ASSISTED REINFORCEMENT LEARNING Full publication and description at https://www.frontiersin.org/articles/10.3389/fphy.2017.00071/full Reinforcement learning and motivation • Rewarding good results, i.e., simulating millions of parking maneuvers and rewarding successful ones. • Agents, such as self-driving vehicles, intend to find the best thing to do in a given situation to reach their goal (parking, maneuvering through traffic, etc.) – they learn by trial and error. Goal: the closer to the real-world simulations are, the better the results • As the world is dynamic, the agent may need to consider new observations/ data it hasn‘t seen before and adapt it‘s strategy. • Given time-constraints, quantum-enhanced reinforcement learning has the potential to help agents analyze and learn quicker Next steps • Apply to far more complex real-world scenarios 7 QUANTUM-ASSISTED CLUSTERING Full publication and description at https://arxiv.org/abs/1803.02886 Motivation • Clustering is useful in a variety of applications, especially for uncovering and understanding network behavior, i.e.: • model how something can move through a network. For example, malicious software will propagate more quickly through a dense community, compared to a sparse one • extrapolate insight about organizational structures from complex communications meta-data • look at clusters of fraudulent activity Goal • Invent a quantum-enhanced clustering algorithm that‘s more accurate and faster than purely classical clustering algorithms Actual status and next steps • First, quantum-enhanced clustering algorithm in place 8 • Application to complex real-world scenarios, i.e., cyber security Quantum Artificial Neural Network (1) Motivation 459 • Artificial neural networks may be used '5-9- '5%9- '579- '569- = '5-96 '5%96 '5796 '5696 whenever software cannot be explicitly 8 8 8 8 programmed to solve a task (or only - % 7 : with significant effort). • Optimize a performance criterion using h1 w 1 i1h h1 w o1 example data or past experience. w w i1 i1 h2 h w 1 o n i1 w h 3 i 1 h n wh2o1 Goal h2 o1 1 h 2 w i 2 h2 wwi2h on w i2 i2h • Implement a QNN and verify if either w 3 o1 h3 i2 h w n 1 w h h3on performance or accuracy can be n 2 i h h3 on in w w winh3 improved compared to a classical ANN. 1 o in 4 w h in w on hn h4 w '/-5- '/%5- '/65- Actual status h n '/-5% '/%5% '/65% • First QNN in place. 4/5 = '/-57 '/%57 '/657 . 0 '/-56 '/%56 '/656 • Application to complex real-world ! = ℎ (' + *' ℎ (' + *' ! )) + 3 8 8 8 scenarios, i.e., MNIST data set. " % ( + - (+ /+ "1/ " - % 7 +,- /,- 9 Quantum Artificial Neural Network (2) A very, very simple example • The D-Wave solves 0 0 0 !"# $, & = $( ) & ) $ *+ = -, 0 1 +/ +/ where $ is the input vector, and & describes the ( ( *+ = = = -, * *+ = * -, 1 0 +9 + relation between the variables. 9 + + + = *(* ./*(-, 1 1 / 9 • Existing quantum-assisted ANN approaches sample the weightspace. *+ = * *(* ./*(-, = &-, arg min &-, • In our approach, we represent samples, 6 weights and target variables as matrix and If -, is a free vector, &-, is not free but its components are. & is a projection evaluate different configurations of the QNN operator as described below, and -, is the target vector. in one annealing cycle. 0 We represent &-, for 0 Target 1 Input Next steps different weight 0 1 vectors on the chip 0 0 See what this approach can be used for: at once. For a simple 1 • Weight initializer for classical ANN training QNN, we tested it for Projection up to 20 QNNs at 0 • Full ANN trainer once. 0 0 0 • Train on MNIST 0 1 10 1 Input 0 ELECTRONIC STRUCTURE CALCULATIONS (1) Motivation • With classical computers our calculations describe properties such as a molecule’s ground-state energy by using the Schrödinger equation to calculate mathematical parameters called wave functions. • Classical computers can solve such problems exactly only for elementary molecules because of the great complexity of the many interactions of the multiple subatomic particles found in larger compounds. • Exact solutions rapidly become unfeasible, even for the fastest computers working over the entire lifetime of the universe. • Quantum computers do not require exponentially increasing time to solve larger and larger systems, so they do not suffer the same limitations. Goal • Find advanced materials 11 ELECTRONIC STRUCTURE CALCULATIONS (2) • Electronic structure problems are mainly targeted by • Molecules can be described by a fermionic Hamiltonian gate model approaches 1 + = -ℎ % )*) + - ℎ (%))*)*) ) • Different quantum algorithms, as the variational "# " # 2 "#'( " # ' ( quantum Eigensolver (VQE) or the phase estimation ",# ",#,',( algorithm (PEA), were developed to find the ground state of small molecules • ℎ"#(%) and ℎ"#'((%) are the one- and two-electron integrals for a specific interatomic distance , * and • But: current gate model devices suffer from different % )" )" challenges: are the fermionic creation and annihilation operators • Small number of qubits • As quantum devices use qubits, we have to map the fermionic operators onto qubit operators (e.g. by Jordan- • Decoherence effects Wigner transformation) • Imperfect qubits and gates " " "# " # "#' " # ' + = - ℎ232 + - ℎ2432 34 + - ℎ2453234 35 + ⋯ ",2 ",#,2,4 ",#,',2,4,5 12 ELECTRONIC STRUCTURE CALCULATIONS (3) • Hamiltonian consisting of qubit operators only, + + +/ + / +/1 + / 1 ( = * ℎ,!, + * ℎ,0!, !0 + * ℎ,02!,!0 !2 + ⋯ but how to map it on a QUBO? +,, +,/,,,0 +,/,1,,,0,2 • !", !$ and !% terms instead of !% terms only • Reducing the dimensions from =-local to 2-local by • k-local terms instead of 2-local using ancillary qubits • Illustrative example: • Below we show how to map such a &-qubit min ±DEDFDG = min ±DHDG + DEDF − 2DEDH − 2DFDH + 3DH Hamiltonian with !", !$ and !% terms to a DE, DF , DGDH ∈ 0,1 '&-qubit Hamiltonian with !% terms only • This can be used for finding a 2-local representation, +7 +8 +8 +7 1 − ! !% !% − ! yielding the standard Ising Hamiltonian: !+ → % :; < :; = !+ → > % :; < :; = " 2 $ 2 +7 + +7 + 8 8 ; + ; + / + !% − !% ; ; + 1 + !% !% ; ; ( = * ℎ+ !% + * L+/!%!% !% → : < : = ? → : < : = 2 2 + +,/ 13 ELECTRONIC STRUCTURE CALCULATIONS (4) Neural network prediction Sometimes the QPU calculations are a little off 14 QUANTUM FINITE ELEMENTS METHOD Motivation • The finite elements method is used to optimize parts design in order to minimize a quantity, i.e., minimize the sound pressure at a given position around a part, or maximize the durability at certain areas. • The elements influence each other, so a natural assumption is that qubits connected via couplers can be used to represent it. Goal • Invent a quantum-assisted

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