Applications such as simulating complicated quantum systems or solving large-scale linear
algebra problems are very challenging for classical computers, owing to the extremely high …

Quantum mechanics, the subfield of physics that describes the behavior of very small
(quantum) particles, provides the basis for a new paradigm of computing. First proposed in …

We describe and benchmark a new quantum charge-coupled device (QCCD) trapped-ion
quantum computer based on a linear trap with periodic boundary conditions, which …

Interactions in quantum systems can spread initially localized quantum information into the
exponentially many degrees of freedom of the entire system. Understanding this process …

Variational quantum algorithms, a popular heuristic for near-term quantum computers, utilize
parameterized quantum circuits which naturally express Lie groups. It has been postulated …

To explore the possibilities of a near-term intermediate-scale quantum algorithm and long-
term fault-tolerant quantum computing, a fast and versatile quantum circuit simulator is …

The famous, yet unsolved, Fermi-Hubbard model for strongly-correlated electronic systems
is a prominent target for quantum computers. However, accurately representing the Fermi …

We propose a tomographic protocol for estimating any k-body reduced density matrix (k-
RDM) of an n-mode fermionic state, a ubiquitous step in near-term quantum algorithms for …

Quantum circuits consisting of random unitary gates and subject to local measurements
have been shown to undergo a phase transition, tuned by the rate of measurement, from a …

We give new evidence that quantum computers--moreover, rudimentary quantum computers
built entirely out of linear-optical elements--cannot be efficiently simulated by classical …