A state-averaged orbital-optimized hybrid quantum-classical algorithm for a democratic description of ground and excited states

• URL: http://arxiv.org/abs/2009.11417v2
• Date: Thu, 14 Jan 2021 12:47:23 GMT
• Title: A state-averaged orbital-optimized hybrid quantum-classical algorithm for a democratic description of ground and excited states
• Authors: Saad Yalouz, Bruno Senjean, Jakob G\"unther, Francesco Buda, Thomas E. O'Brien, Lucas Visscher
• Abstract summary: In the Noisy Intermediate-Scale Quantum (NISQ) era, solving the electronic structure problem from chemistry is considered as the "killer application" We introduce a method called "State-Averaged Orbital-d Variationalsolver" (SA-OO-VQE) which combines two algorithms. We show that merging both algorithms fulfil the necessary condition to describe the molecule's conical intersection.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: In the Noisy Intermediate-Scale Quantum (NISQ) era, solving the electronic structure problem from chemistry is considered as the "killer application" for near-term quantum devices. In spite of the success of variational hybrid quantum/classical algorithms in providing accurate energy profiles for small molecules, careful considerations are still required for the description of complicated features of potential energy surfaces. Because the current quantum resources are very limited, it is common to focus on a restricted part of the Hilbert space (determined by the set of active orbitals). While physically motivated, this approximation can severely impact the description of these complicated features. A perfect example is that of conical intersections (i.e. a singular point of degeneracy between electronic states), which are of primary importance to understand many prominent reactions. Designing active spaces so that the improved accuracy from a quantum computer is not rendered useless is key to finding useful applications of these promising devices within the field of chemistry. To answer this issue, we introduce a NISQ-friendly method called "State-Averaged Orbital-Optimized Variational Quantum Eigensolver" (SA-OO-VQE) which combines two algorithms: (1) a state-averaged orbital-optimizer, and (2) a state-averaged VQE. To demonstrate the success of the method, we classically simulate it on a minimal Schiff base model (namely the formaldimine molecule CH2NH) relevant also for the photoisomerization in rhodopsin -- a crucial step in the process of vision mediated by the presence of a conical intersection. We show that merging both algorithms fulfil the necessary condition to describe the molecule's conical intersection, i.e. the ability to treat degenerate (or quasi-degenerate) states on the same footing.

Related papers

• Hybrid Quantum-Classical Clustering for Preparing a Prior Distribution of Eigenspectrum [10.950807972899575]
  We consider preparing the prior distribution and circuits for the eigenspectrum of time-independent Hamiltonians. The proposed algorithm unfolds in three strategic steps: Hamiltonian transformation, parameter representation, and classical clustering. The algorithm is showcased through applications to the 1D Heisenberg system and the LiH molecular system.
  arXiv  Detail & Related papers  (2024-06-29T14:21:55Z)
• Variational quantum eigensolver for closed-shell molecules with non-bosonic corrections [6.3235499003745455]
  We introduce a simple correction scheme in the electron correlation model approximated by the geometrical mean of the bosonic terms. We find our non-bosonic correction method reaches reliable quantum chemistry simulations at least for the tested systems.
  arXiv  Detail & Related papers  (2023-10-11T16:47:45Z)
• A self-consistent field approach for the variational quantum eigensolver: orbital optimization goes adaptive [52.77024349608834]
  We present a self consistent field approach (SCF) within the Adaptive Derivative-Assembled Problem-Assembled Ansatz Variational Eigensolver (ADAPTVQE) This framework is used for efficient quantum simulations of chemical systems on nearterm quantum computers.
  arXiv  Detail & Related papers  (2022-12-21T23:15:17Z)
• Quantum Davidson Algorithm for Excited States [42.666709382892265]
  We introduce the quantum Krylov subspace (QKS) method to address both ground and excited states. By using the residues of eigenstates to expand the Krylov subspace, we formulate a compact subspace that aligns closely with the exact solutions. Using quantum simulators, we employ the novel QDavidson algorithm to delve into the excited state properties of various systems.
  arXiv  Detail & Related papers  (2022-04-22T15:03:03Z)
• Quantum Computing in Pharma: A Multilayer Embedding Approach for Near Future Applications [0.0]
  The quantum computer excels at treating a moderate number of orbitals within an active space in a fully quantum mechanical manner. We present a quantum phase estimation calculation on F$enzi$ in a (2,2) active space on Rigetti's Aspen-11 QPU.
  arXiv  Detail & Related papers  (2022-02-09T13:39:22Z)
• Interactive Protocols for Classically-Verifiable Quantum Advantage [46.093185827838035]
  "Interactions" between a prover and a verifier can bridge the gap between verifiability and implementation. We demonstrate the first implementation of an interactive quantum advantage protocol, using an ion trap quantum computer.
  arXiv  Detail & Related papers  (2021-12-09T19:00:00Z)
• Computing molecular excited states on a D-Wave quantum annealer [52.5289706853773]
  We demonstrate the use of a D-Wave quantum annealer for the calculation of excited electronic states of molecular systems. These simulations play an important role in a number of areas, such as photovoltaics, semiconductor technology and nanoscience.
  arXiv  Detail & Related papers  (2021-07-01T01:02:17Z)
• Hybrid Quantum-Classical Eigensolver Without Variation or Parametric Gates [0.0]
  We present a process for obtaining the eigenenergy spectrum of electronic quantum systems. This is achieved by projecting the Hamiltonian of a quantum system onto a limited effective Hilbert space. A process for preparing short depth quantum circuits to measure the corresponding diagonal and off-diagonal terms of the effective Hamiltonian is given.
  arXiv  Detail & Related papers  (2020-08-26T02:31:24Z)
• Gate-free state preparation for fast variational quantum eigensolver simulations: ctrl-VQE [0.0]
  VQE is currently the flagship algorithm for solving electronic structure problems on near-term quantum computers. We propose an alternative algorithm where the quantum circuit used for state preparation is removed entirely and replaced by a quantum control routine. As with VQE, the objective function optimized is the expectation value of the qubit-mapped molecular Hamiltonian.
  arXiv  Detail & Related papers  (2020-08-10T17:53:09Z)
• Quantum-optimal-control-inspired ansatz for variational quantum algorithms [105.54048699217668]
  A central component of variational quantum algorithms (VQA) is the state-preparation circuit, also known as ansatz or variational form. Here, we show that this approach is not always advantageous by introducing ans"atze that incorporate symmetry-breaking unitaries. This work constitutes a first step towards the development of a more general class of symmetry-breaking ans"atze with applications to physics and chemistry problems.
  arXiv  Detail & Related papers  (2020-08-03T18:00:05Z)
• Einselection from incompatible decoherence channels [62.997667081978825]
  We analyze an open quantum dynamics inspired by CQED experiments with two non-commuting Lindblad operators. We show that Fock states remain the most robust states to decoherence up to a critical coupling.
  arXiv  Detail & Related papers  (2020-01-29T14:15:19Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.