Quantum Computing
Our team is advancing the frontier of quantum simulations for particle physics, with a focus on nuclear effective field theories (EFTs) relevant to neutrino interactions. We explore fault-tolerant quantum algorithms for simulating nuclear dynamics, from ground-state preparation to observable extraction. By comparing qubit-based and hybrid oscillator–qubit platforms, we aim to reduce the resource overhead of simulating pion dynamics, opening new possibilities for tackling classically intractable problems in neutrino-nucleus scattering.
Quantum computing is an exciting pathway to new and improved calculations in a wide range of areas, and it offers a route to overcome classical barriers —such as the sign problem in real‐time evolution— that plague high‐energy physics simulations.
Nuclear effective field theories (EFTs) treat protons and neutrons as nonrelativistic fermions, offering a simpler alternative to lattice QCD by reducing degrees of freedom while still capturing the essential physics for most observables. These theories can be implemented using quantum computing algorithms that address the following components:
- State preparation: Constructing a desired initial quantum state for our qubits, such as the ground state for our theory.
- Time evolution: Simulating the dynamical evolution of a system under the effective Hamiltonian, enabling the study of scattering processes.
- Observable estimation: Extracting useful physical information from the evolved quantum state through appropriate quantum measurements.
There are several algorithmic strategies we explore to carry out these three steps, incurring different computational costs (qubit and gate requirements) and with different levels of accuracy of the outcomes.
Neutrino‐induced pion production on nuclear targets is a key process for modern experiments, which must be quantitatively understood to reconstruct neutrino energy accurately. On qubit-based platforms, however, including dynamical pions in the theory inflates gate counts by roughly 30 orders of magnitude over pionless EFTs: truncating the unbounded bosonic Fock space, discretizing field amplitudes or binary encodings of occupation-numbers, and synthesizing creation/annihilation operators all add substantial overhead and error. Hybrid oscillator–qubit processors in circuit QED architectures combine superconducting qubits with high-Q microwave cavities—realising bosonic modes as photon excitations of a harmonic oscillator—and offer universal control via experimentally realisable gates. We assess whether these platforms can cut the cost of simulating nuclear EFTs with explicit pions for neutrino-interaction observables and seek to pinpoint the regimes where native bosonic computational resources provide the greatest advantage.
Whether using qubit-based or native bosonic computational architectures, quantum error correction remains a central challenge for useful and scalable quantum computation. Quantum states are inherently fragile and quantum information processing is susceptible to decoherence, loss and environmental noise. Quantum Error Correction (QEC) is a foundational technology for quantum computation. Several QEC codes have been developed, all based on the key idea of encoding quantum information over many entangled physical qubits in a way that protects quantum information in specially designed subspaces of a larger Hilbert space. However, implementing QEC imposes substantial computational overheads. Our aim is to study a comprehensive path towards Nuclear EFT simulations for early Fault-Tolerant quantum computers, including the estimation of the resources needed to execute the algorithms in quantum hardware.
Team Leader
- Prof. Costas Andreopoulos
PhD Students
- Marina Maneyro
- Sam Godwood