Quantum Inspired Excited States Calculations for Molecules Based on Contextual Subspace and Symmetry Optimizations

• URL: http://arxiv.org/abs/2502.17932v1
• Date: Tue, 25 Feb 2025 07:48:04 GMT
• Title: Quantum Inspired Excited States Calculations for Molecules Based on Contextual Subspace and Symmetry Optimizations
• Authors: Qianjun Yao, He Li,
• Abstract summary: Quantum-inspired methods for excited-state calculations remain underexplored in Noisy Intermediate-Scale Quantum (NISQ) hardware.<n>We propose a resource-efficient framework that integrates the contextual subspace (CS) method with the Variational Quantum Deflation (VQD) algorithm.<n>We demonstrate that the implementation of a spin-conserving hardware-efficient ansatz, namely the $mathcalN(theta_x,theta_y,theta_z)$ block ansatz, allows exploitation of spin symmetry within the projected subspace.
• Score: 2.2322840607996883
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Quantum-inspired methods for excited-state calculations remain underexplored in Noisy Intermediate-Scale Quantum (NISQ) hardware, despite their critical role in photochemistry and material science. Here, we propose a resource-efficient framework that integrates the contextual subspace (CS) method with the Variational Quantum Deflation (VQD) algorithm to enable systematic excited-state calculations for molecules while reducing qubit requirements. On the basis of the numerical results, we find that it is unproblematic to utilize this combination in calculating the excited state to reduce qubits. Furthermore, we demonstrate that the implementation of a spin-conserving hardware-efficient ansatz, namely the $\mathcal{N}(\theta_x,\theta_y,\theta_z)$ block ansatz, allows exploitation of spin symmetry within the projected subspace, thereby achieving further reductions in computational resource demands. Compared to the commonly used $R_{y}R_{z}$ ansatz, using the $\mathcal{N}(\theta_x,\theta_y,\theta_z)$ ansatz can reduce the number of optimization iterations by up to 3 times at a similar circuit depth.

Related papers

• Branch-and-bound digitized counterdiabatic quantum optimization [39.58317527488534]
  Branch-and-bound algorithms effectively solve convex optimization problems, relying on the relaxation the objective function to obtain tight lower bounds. We propose a branch-and-bound digitized counterdiabatic quantum optimization (BB-DCQO) algorithm that addresses the relaxation difficulties.
  arXiv  Detail & Related papers  (2025-04-21T18:19:19Z)
• Practical Application of the Quantum Carleman Lattice Boltzmann Method in Industrial CFD Simulations [44.99833362998488]
  This work presents a practical numerical assessment of a hybrid quantum-classical approach to CFD based on the Lattice Boltzmann Method (LBM) We evaluate this method on three benchmark cases featuring different boundary conditions, periodic, bounceback, and moving wall. Our results confirm the validity of the approach, achieving median error fidelities on the order of $10-3$ and success probabilities sufficient for practical quantum state sampling.
  arXiv  Detail & Related papers  (2025-04-17T15:41:48Z)
• Reducing QUBO Density by Factoring Out Semi-Symmetries [4.581191399651181]
  We introduce the concept of textitsemi-symmetries in QUBO matrices. We show that our algorithm reduces the number of couplings and circuit depth by up to $45%.
  arXiv  Detail & Related papers  (2024-12-18T12:05:18Z)
• Hardware-efficient variational quantum algorithm in trapped-ion quantum computer [0.0]
  We study a hardware-efficient variational quantum algorithm ansatz tailored for the trapped-ion quantum simulator, HEA-TI. We leverage programmable single-qubit rotations and global spin-spin interactions among all ions, reducing the dependence on resource-intensive two-qubit gates in conventional gate-based methods.
  arXiv  Detail & Related papers  (2024-07-03T14:02:20Z)
• Calculating response functions of coupled oscillators using quantum phase estimation [40.31060267062305]
  We study the problem of estimating frequency response functions of systems of coupled, classical harmonic oscillators using a quantum computer. Our proposed quantum algorithm operates in the standard $s-sparse, oracle-based query access model. We show that a simple adaptation of our algorithm solves the random glued-trees problem in time.
  arXiv  Detail & Related papers  (2024-05-14T15:28:37Z)
• Hybrid Quantum-Classical Scheduling for Accelerating Neural Network Training with Newton's Gradient Descent [37.59299233291882]
  We propose Q-Newton, a hybrid quantum-classical scheduler for accelerating neural network training with Newton's GD. Q-Newton utilizes a streamlined scheduling module that coordinates between quantum and classical linear solvers. Our evaluation showcases the potential for Q-Newton to significantly reduce the total training time compared to commonly used quantum machines.
  arXiv  Detail & Related papers  (2024-04-30T23:55:03Z)
• Solving lattice gauge theories using the quantum Krylov algorithm and qubitization [0.0]
  We investigate using the quantum subspace expansion algorithm to compute the groundstate of the Schwinger model. We present a full analysis of the resources required to compute LGT vacuum states using a quantum algorithm using qubitization.
  arXiv  Detail & Related papers  (2024-03-13T18:00:01Z)
• Towards large-scale quantum optimization solvers with few qubits [59.63282173947468]
  We introduce a variational quantum solver for optimizations over $m=mathcalO(nk)$ binary variables using only $n$ qubits, with tunable $k>1$. We analytically prove that the specific qubit-efficient encoding brings in a super-polynomial mitigation of barren plateaus as a built-in feature.
  arXiv  Detail & Related papers  (2024-01-17T18:59:38Z)
• Quantum Semidefinite Programming with Thermal Pure Quantum States [0.5639904484784125]
  We show that a quantization'' of the matrix multiplicative-weight algorithm can provide approximate solutions to SDPs quadratically faster than the best classical algorithms. We propose a modification of this quantum algorithm and show that a similar speedup can be obtained by replacing the Gibbs-state sampler with the preparation of thermal pure quantum (TPQ) states.
  arXiv  Detail & Related papers  (2023-10-11T18:00:53Z)
• GRAPE optimization for open quantum systems with time-dependent decoherence rates driven by coherent and incoherent controls [77.34726150561087]
  The GRadient Ascent Pulse Engineering (GRAPE) method is widely used for optimization in quantum control. We adopt GRAPE method for optimizing objective functionals for open quantum systems driven by both coherent and incoherent controls. The efficiency of the algorithm is demonstrated through numerical simulations for the state-to-state transition problem.
  arXiv  Detail & Related papers  (2023-07-17T13:37:18Z)
• Quantum Computing Provides Exponential Regret Improvement in Episodic Reinforcement Learning [35.11103784048256]
  We propose an textitUpper Confidence Bound (UCB) based quantum algorithmic framework to facilitate learning of a finite-horizon MDP. Our quantum algorithm achieves an exponential improvement in regret as compared to the classical counterparts.
  arXiv  Detail & Related papers  (2023-02-16T23:01:27Z)
• Digital-analog co-design of the Harrow-Hassidim-Lloyd algorithm [0.0]
  Harrow-Hassidim-Lloyd quantum algorithm was proposed to solve linear systems of equations $Avecx = vecb$. There is not an explicit quantum circuit for the subroutine which maps the inverse of the problem matrix $A$ into an ancillary qubit. We present a co-designed quantum processor which reduces the depth of the algorithm.
  arXiv  Detail & Related papers  (2022-07-27T13:58:13Z)
• Improving Quantum Simulation Efficiency of Final State Radiation with Dynamic Quantum Circuits [1.3375143521862154]
  We make use of a new quantum hardware capability called dynamical quantum computing to improve the scaling of the QPS algorithm. We modify the quantum parton shower circuit to incorporate mid-circuit qubit measurements, resets, and quantum operations conditioned on classical information.
  arXiv  Detail & Related papers  (2022-03-18T15:31:19Z)
• Realization of arbitrary doubly-controlled quantum phase gates [62.997667081978825]
  We introduce a high-fidelity gate set inspired by a proposal for near-term quantum advantage in optimization problems. By orchestrating coherent, multi-level control over three transmon qutrits, we synthesize a family of deterministic, continuous-angle quantum phase gates acting in the natural three-qubit computational basis.
  arXiv  Detail & Related papers  (2021-08-03T17:49:09Z)

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.