# Progress towards practical quantum variational algorithms

@article{Wecker2015ProgressTP, title={Progress towards practical quantum variational algorithms}, author={Dave Wecker and Matthew B. Hastings and Matthias Troyer}, journal={Physical Review A}, year={2015}, volume={92}, pages={042303} }

The preparation of quantum states using short quantum circuits is one of the most promising near-term applications of small quantum computers, especially if the circuit is short enough and the fidelity of gates high enough that it can be executed without quantum error correction. Such quantum state preparation can be used in variational approaches, optimizing parameters in the circuit to minimize the energy of the constructed quantum state for a given problem Hamiltonian. For this purpose we… Expand

#### 267 Citations

Quantum optimization using variational algorithms on near-term quantum devices

- Computer Science, Physics
- Quantum Science and Technology
- 2018

The quantum volume as a metric to compare the power of near-term quantum devices is discussed and simple error-mitigation schemes are introduced that could improve the accuracy of determining ground-state energies. Expand

Low-depth circuit ansatz for preparing correlated fermionic states on a quantum computer

- Physics, Mathematics
- Quantum Science and Technology
- 2019

Quantum simulations are bound to be one of the main applications of near-term quantum computers. Quantum chemistry and condensed matter physics are expected to benefit from these technological… Expand

Variational Quantum Algorithms

- Computer Science, Physics
- Nature Reviews Physics
- 2021

An overview of the field of Variational Quantum Algorithms is presented and strategies to overcome their challenges as well as the exciting prospects for using them as a means to obtain quantum advantage are discussed. Expand

Variational Quantum Information Processing

- Computer Science
- 2019

This dissertation presents the application of the variational quantum computing approach to problems in quantum simulation, quantum state preparation, quantum error-correction, and generative modeling, and establishes practical guidelines to implement these methods on near-term quantum computers. Expand

Hardware-efficient variational quantum eigensolver for small molecules and quantum magnets

- Physics, Medicine
- Nature
- 2017

The experimental optimization of Hamiltonian problems with up to six qubits and more than one hundred Pauli terms is demonstrated, determining the ground-state energy for molecules of increasing size, up to BeH2. Expand

Simulating Large Quantum Circuits on a Small Quantum Computer.

- Medicine, Physics
- Physical review letters
- 2020

This Letter introduces cluster parameters K and d of a quantum circuit and proposes a cluster simulation scheme that can simulate any (K,d)-clustered quantum circuit on a d-qubit machine in time roughly 2^{O(K)}, with further speedups possible when taking more fine-grained circuit structure into account. Expand

Efficient variational simulation of non-trivial quantum states

- Physics
- SciPost Physics
- 2019

We provide an efficient and general route for preparing non-trivial
quantum states that are not adiabatically connected to unentangled
product states. Our approach is a hybrid quantum-classical… Expand

Variational Quantum Simulation of Chemical Dynamics with Quantum Computers

- Physics
- 2021

Classical simulation of real-space quantum dynamics is challenging due to the exponential scaling of computational cost with system dimensions. Quantum computer offers the potential to simulate… Expand

Using gradient-based algorithms to determine ground state energies on a quantum computer

- Physics
- 2021

Variational algorithms are promising candidates to be implemented on near-term quantum computers. The variational quantum eigensolver (VQE) is a prominent example, where a parametrized trial state of… Expand

Hybrid quantum-classical approach to correlated materials

- Computer Science, Physics
- 2015

This work shows that by using a hybrid quantum-classical algorithm that incorporates the power of a small quantum computer into a framework of classical embedding algorithms, the electronic structure of complex correlated materials can be efficiently tackled using a quantum computer. Expand

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