
Quantum algorithms for reinforcement learning with a generative model
Daochen Wang,
Aarthi Sundaram,
Robin Kothari,
Ashish Kapoor,
Martin Roetteler
ICML 2021:
slides,
talk,
poster
[PKU CFCS]
[QTML 2021: slides]
[QISENET: slides]
We quantify the quantum speedups achievable for reinforcement learning
in terms of calls to a generative model of the underlying
Markov decision process.


Quantum exploration algorithms for multiarmed bandits
Daochen Wang*,
Xuchen You*,
Tongyang Li,
Andrew M. Childs
AAAI 2021: talk
[INFORMS 2021]
[GMU: slides]
[QTML 2020: slides, talk]
[MSR: slides]
We construct an optimal quantum algorithm for identifying the best arm in a
multiarmed bandit that is quadratically faster than any classical algorithm.


Symmetries, graph properties, and quantum speedups
Shalev BenDavid,
Andrew M. Childs,
András Gilyén,
William Kretschmer,
Supartha Podder,
Daochen Wang^{†}
FOCS 2020:
short slides,
short talk,
long talk
[ASQC 2022]
[APS 2021: slides]
[QIP 2021: talk]
[MSR: slides]
We characterise how a problem's symmetries determine whether quantum computation can drastically
speed up its solution; it turns out that graph symmetries play the key role.
Subsumes our earlier work [Property Testing Review].


Efficient quantum measurement of Pauli operators
in the presence of finite sampling error
Ophelia Crawford*,
Barnaby van Straaten*,
Daochen Wang*,
Thomas Parks,
Earl Campbell,
Stephen Brierley
Quantum 2021
[QTurn 2020]
[QCTIP 2020: talk]
We reduce the number of measurements needed to estimate the expectation value of an observable by a few orders of magnitude via simultaneous measurements.


Possibilistic simulation of quantum circuits by classical circuits
Daochen Wang
Physical Review A 2022
I extract a notion of "psimulation" from
a breakthrough paper in 2018
and then construct explicit classical circuits that can psimulate any quantum circuit.


Variational quantum computation of excited states
Oscar Higgott,
Daochen Wang,
Stephen Brierley
Quantum 2019
[QCTIP 2019]
We enable the
variational quantum eigensolver to compute excited states at little extra cost by penalising overlaps between quantum states.


Accelerated variational quantum eigensolver
Daochen Wang,
Oscar Higgott,
Stephen Brierley
Physical Review Letters 2019
We accelerate the
variational quantum eigensolver by making it
behave more like
quantum phase estimation as more coherence time becomes available.


Driving Rabi oscillations at the giant dipole resonance in xenon
Stefan Pabst,
Daochen Wang,
Robin Santra
Physical Review A 2015
We find that supershort yet superintense pulses of light can drive Rabi oscillations between bound states of negative energy and a pseudobound state of positive energy.


OpenFermion: the electronic structure package for quantum computers
Jarrod R. McClean,
Kevin J. Sung, Ian D. Kivlichan, Yudong Cao, Chengyu Dai, E. Schuyler Fried,
Craig Gidney,
Brendan Gimby,
Pranav Gokhale,
Thomas Häner, Tarini Hardikar, Vojtěch Havlíček,
Oscar Higgott, Cupjin Huang,
Josh Izaac,
Zhang Jiang, Xinle Liu, Sam McArdle, Matthew Neeley,
Thomas O'Brien, Bryan O'Gorman, Isil Ozfidan,
Maxwell D. Radin,
Jhonathan Romero,
Nicholas Rubin,
Nicolas P. D. Sawaya, Kanav Setia, Sukin Sim, Damian S. Steiger, Mark Steudtner,
Qiming Sun, Wei Sun,
Daochen Wang, Fang Zhang, Ryan Babbush
Quantum Science and Technology 2020
[GitHub]
I contributed code that allows you to automatically retrieve molecular geometries from the
PubChem database  try: geometry_from_pubchem('water').


I was the teaching assistant for the following class

