Iterative Qubit Coupled Cluster using only Clifford circuits

• URL: http://arxiv.org/abs/2211.10501v2
• Date: Mon, 04 Nov 2024 19:23:25 GMT
• Title: Iterative Qubit Coupled Cluster using only Clifford circuits
• Authors: James Brown, Marc P. Coons, Erika Lloyd, Alexandre Fleury, Krzysztof Bieniasz, Valentin Senicourt, Arman Zaribafiyan,
• Abstract summary: An ideal state preparation protocol can be characterized by being easily generated classically. We propose a method that meets these requirements by introducing a variant of the iterative qubit coupled cluster (iQCC) We demonstrate the algorithm's correctness in ground-state simulations and extend our study to complex systems like the titanium-based compound Ti(C5H5)(CH3)3 with a (20, 20) active space.
• Score: 36.136619420474766
• License:
• Abstract: The performance of quantum algorithms for ground-state energy estimation is directly impacted by the quality of the initial state, where quality is traditionally defined in terms of the overlap of the input state with the target state. An ideal state preparation protocol can be characterized by being easily generated classically and can be transformed to a quantum circuit with minimal overhead while having a significant overlap with the targeted eigenstate of a given Hamiltonian. We propose a method that meets these requirements by introducing a variant of the iterative qubit coupled cluster (iQCC) approach, which exclusively uses Clifford circuits. These circuits can be efficiently simulated on a classical computer, with polynomial scaling according to the Gottesman-Knill theorem. Since the iQCC method has been developed as a quantum algorithm firstly, our variant can be mapped naturally to quantum hardware. We additionally implemented several optimizations to the algorithm enhancing its scalability. We demonstrate the algorithm's correctness in ground-state simulations for small molecules such as H2, LiH, and H2O, and extend our study to complex systems like the titanium-based compound Ti(C5H5)(CH3)3 with a (20, 20) active space, requiring 40 qubits. Results show that the convergence of the algorithm is well-behaved, and the ground state can be represented accurately. Moreover, we show an automated workflow for restricting the qubit active space, thus relieving computational resources by considering only qubits affected by non-trivial operations.

Related papers

• Efficient Learning for Linear Properties of Bounded-Gate Quantum Circuits [63.733312560668274]
  Given a quantum circuit containing d tunable RZ gates and G-d Clifford gates, can a learner perform purely classical inference to efficiently predict its linear properties? We prove that the sample complexity scaling linearly in d is necessary and sufficient to achieve a small prediction error, while the corresponding computational complexity may scale exponentially in d. We devise a kernel-based learning model capable of trading off prediction error and computational complexity, transitioning from exponential to scaling in many practical settings.
  arXiv  Detail & Related papers  (2024-08-22T08:21:28Z)
• Concurrent VQE for Simulating Excited States of the Schwinger Model [0.0]
  This work explores the application of the concurrent variational quantum eigensolver (cVQE) for computing excited states of the Schwinger model. We show how to efficiently obtain the lowest two, four, and eight eigenstates with one, two, and three ancillary qubits for both vanishing and non-vanishing background electric field cases.
  arXiv  Detail & Related papers  (2024-07-22T13:42:02Z)
• Non-unitary Coupled Cluster Enabled by Mid-circuit Measurements on Quantum Computers [37.69303106863453]
  We propose a state preparation method based on coupled cluster (CC) theory, which is a pillar of quantum chemistry on classical computers. Our approach leads to a reduction of the classical computation overhead, and the number of CNOT and T gates by 28% and 57% on average.
  arXiv  Detail & Related papers  (2024-06-17T14:10:10Z)
• Neutron-nucleus dynamics simulations for quantum computers [49.369935809497214]
  We develop a novel quantum algorithm for neutron-nucleus simulations with general potentials. It provides acceptable bound-state energies even in the presence of noise, through the noise-resilient training method. We introduce a new commutativity scheme called distance-grouped commutativity (DGC) and compare its performance with the well-known qubit-commutativity scheme.
  arXiv  Detail & Related papers  (2024-02-22T16:33:48Z)
• Enhancing Scalability of Quantum Eigenvalue Transformation of Unitary Matrices for Ground State Preparation through Adaptive Finer Filtering [0.13108652488669736]
  Hamiltonian simulation is a domain where quantum computers have the potential to outperform classical counterparts. One of the main challenges of such quantum algorithms is up-scaling the system size. We present an approach to improve the scalability of eigenspace filtering for the ground state preparation of a given Hamiltonian.
  arXiv  Detail & Related papers  (2024-01-17T09:52:24Z)
• Mapping quantum circuits to shallow-depth measurement patterns based on graph states [0.0]
  We create a hybrid simulation technique for measurement-based quantum computing. We show that groups of fully commuting operators can be implemented using fully-parallel, i.e., non-adaptive, measurements. We discuss how such circuits can be implemented in constant quantum depths by employing quantum teleportation.
  arXiv  Detail & Related papers  (2023-11-27T19:00:00Z)
• 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)
• Decomposition of Matrix Product States into Shallow Quantum Circuits [62.5210028594015]
  tensor network (TN) algorithms can be mapped to parametrized quantum circuits (PQCs) We propose a new protocol for approximating TN states using realistic quantum circuits. Our results reveal one particular protocol, involving sequential growth and optimization of the quantum circuit, to outperform all other methods.
  arXiv  Detail & Related papers  (2022-09-01T17:08:41Z)
• Error mitigation and quantum-assisted simulation in the error corrected regime [77.34726150561087]
  A standard approach to quantum computing is based on the idea of promoting a classically simulable and fault-tolerant set of operations. We show how the addition of noisy magic resources allows one to boost classical quasiprobability simulations of a quantum circuit.
  arXiv  Detail & Related papers  (2021-03-12T20:58:41Z)
• A posteriori corrections to the Iterative Qubit Coupled Cluster method to minimize the use of quantum resources in large-scale calculations [0.0]
  We present a variety of a posteriori corrections to the iQCC energies to reduce the number of iterations to achieve the desired accuracy. We demonstrate the utility and efficiency of our approach numerically on the examples of 10-qubit N$$ molecule, the 24-qubit H$$O stretch, and 56-qubit singlet-triplet gap calculations.
  arXiv  Detail & Related papers  (2020-09-28T20:57:32Z)

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.