Quantum Simulation of Particle Scattering Processes
PT-CERN Call 2022/2
Instituto Superior Técnico (Universidade de Lisboa)
Portuguese Quantum Institute
Quantum computation (QC) is a new and promising paradigm to accelerate challenging computations, in particular simulations of quantum systems. This ongoing project aims at studying and developing new and more efficient techniques for quantum simulation of scattering processes in the framework of lattice quantum field theory. The topic of the ongoing first year is quantum simulation of scalar field. The scalar field is not only simple enough to isolate the difficulties of quantum simulation, but it is also a first step towards quantum simulation of the Standard Model and in particular of the Higgs sector. The first goal here is to extend known results to simulate scattering of bound states, which is absent in the literature. Then the focus will move to fermionic gauge theories. This will introduce new difficulties. One crucial step for any quantum simulation is finding an efficient way to encode the degrees of freedom (DOF) of a theory into a qubit system. This is particularly challenging for fermionic gauge theories for two main reasons: 1) the tensor-product structure of qubits is not well suited for anti-commutation relations; 2) gauge theories have nonphysical redundancies that have to be eliminated. The second goal of this project is to tackle this problem and to find better ways to encode gauge theories. The full Standard Model in the huge range of energies experimentally accessible today is beyond the capability of any conceivable computational device. Effective field theories (EFT) will play a crucial role in factorizing the full problem into more accessible problems and in separating the energy scales involved in scattering events like at LHC. Part of the work will consist in identifying the effective theories that are at the same time most suited to tackle classically intractable regimes and to reduce the number of redundancies as much as possible. Combining the techniques and results from the first two parts will be the final goal of the project.