Summary:
UCLA researchers from the Division of Physical Sciences and Engineering have developed a quantum algorithm that can calculate excited states in quantum computing.
Background:
Quantum computing operates based on the principle of superposition. While the bits used in classical computing exist in binary (0 or 1), bits in quantum computing (qubits) exist in a superposition of states, exponentially increasing processing power. This requires algorithms, or eigensolvers, that can calculate ground and excited states. While several algorithms are used for ground state calculations, few are available for the excited state. This limits the adoption of quantum computing systems in broad applications. There is an unmet for a quantum algorithm that can calculate the excited states of quantum systems.
Innovation:
UCLA researchers in the Division of Physical Sciences have developed a new quantum algorithm for calculating the excited states using a contracted quantum eigensolver (ES-CQE). ES-CQE uses a contraction of the Schrödinger equation to arrive at a final algorithm which is used to calculate energy states. The algorithm has been used for calculations of molecular orbitals of a rectangular system and can be expanded to other symmetrical cases. This system offers improved speed and accuracy compared to existing methods. The reported technology is as accurate as the Full Configuration Interaction (FCI), which is a computationally expensive but highly precise method for solving electronic structure problems. This algorithm can advance the field of quantum computing by providing accurate and efficient excited state calculations.
Potential Applications:
• Quantum computing
• Noisy intermediate-scale quantum (NISQ) devices
• Cryptography
• Quantum simulation modeling
Advantages:
• As accurate as FCI
• Computationally inexpensive
• Compatible with symmetrical systems
Development-To-Date:
Researchers have implemented the software and evaluated its performance using a rectangular H4 molecular system.
Related Papers:
• Smart, S. E., Welakuh, D. M., Narang, P. Many-Body Excited States with a Contracted Quantum Eigensolver. arXiv:2305.09653 [quant-ph]. https://arxiv.org/abs/2305.09653
Reference:
UCLA Case No. 2023-180
Lead Inventor:
Professor Prineha Narang, UCLA Physical Sciences Division