no code implementations • 4 Apr 2024 • Sabee Grewal, Vishnu Iyer, William Kretschmer, Daniel Liang
We define a quantum learning task called agnostic tomography, where given copies of an arbitrary state $\rho$ and a class of quantum states $\mathcal{C}$, the goal is to output a succinct description of a state that approximates $\rho$ at least as well as any state in $\mathcal{C}$ (up to some small error $\varepsilon$).
no code implementations • 14 Aug 2023 • Sabee Grewal, Vishnu Iyer, William Kretschmer, Daniel Liang
Recent work has shown that $n$-qubit quantum states output by circuits with at most $t$ single-qubit non-Clifford gates can be learned to trace distance $\epsilon$ using $\mathsf{poly}(n, 2^t, 1/\epsilon)$ time and samples.
no code implementations • 22 May 2023 • Sabee Grewal, Vishnu Iyer, William Kretschmer, Daniel Liang
We give a pair of algorithms that efficiently learn a quantum state prepared by Clifford gates and $O(\log n)$ non-Clifford gates.
no code implementations • 29 Sep 2022 • Sabee Grewal, Vishnu Iyer, William Kretschmer, Daniel Liang
We show that quantum states with "low stabilizer complexity" can be efficiently distinguished from Haar-random.
no code implementations • 13 Apr 2022 • Daniel Liang
In particular, one candidate class of circuits for which an efficient learner might have been possible was that of Clifford circuits, since the corresponding set of states generated by such circuits, called stabilizer states, are known to be efficiently PAC learnable (Rocchetto 2018).
no code implementations • 9 Feb 2021 • Aravind Gollakota, Daniel Liang
Our results position the problem of learning stabilizer states as a natural quantum analogue of the classical problem of learning parities: easy in the noiseless setting, but seemingly intractable even with simple forms of noise.
1 code implementation • 27 May 2020 • Daniel Liang, Li Li, Stefan Leichenauer
The quantum approximate optimization algorithm (QAOA) is widely seen as a possible usage of noisy intermediate-scale quantum (NISQ) devices.
Quantum Physics