Daochen Wang · 王 道辰
[last initial] [first name] at gmail dot com

I'm a second-year PhD student at QuICS, Maryland, where I research quantum information and computation. I'm fortunate to be co-advised by Andrew Childs and Carl Miller.

Prior to Maryland, I worked as one of the first two employees of Riverlane, a British quantum computing startup. I graduated in June 2016 with an MMath from Cambridge.

GitHub  ·  LinkedIn

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Research

I'm interested in structures beneath quantum speed-ups, algorithm design, and real-world applications. I currently research speed limits on how fast quantum computers can solve a problem given only the symmetries of that problem.

(*: equal contribution)

1. Efficient quantum measurement of Pauli operators
Ophelia Crawford*, Barnaby van Straaten*, Daochen Wang*,
Thomas Parks, Earl Campbell, Stephen Brierley
arXiv preprint, August 2019

The number of measurements needed to estimate the average value of an observable can be reduced by a few orders of magnitude via simultaneous measurements - when done in the right way.

2. Simulating quantum circuits by classical circuits
Daochen Wang
arXiv preprint, July 2019
[Poster]

I extract a notion of "p-simulation" from a breakthrough paper in 2018 and then construct explicit classical circuits that can p-simulate any quantum circuit.

3. Variational quantum computation of excited states
Oscar Higgott, Daochen Wang, Stephen Brierley
Quantum, July 2019

Penalising overlaps between quantum states enables the variational quantum eigensolver to compute excited states at essentially no extra cost.

4. Accelerated variational quantum eigensolver
Daochen Wang, Oscar Higgott, Stephen Brierley
Physical Review Letters, April 2019
[Poster]

Given greater coherence times, the variational quantum eigensolver can be made faster by making it behave more like quantum phase estimation.

5. Driving Rabi oscillations at the giant dipole resonance in xenon
Stefan Pabst, Daochen Wang, Robin Santra
Physical Review A, November 2015

Super-short yet super-intense pulses of light can drive electrons up and down between standard bound states of negative energy and a pseudo-bound state of positive energy.

Coding
1. 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
arXiv preprint, February 2019
[GitHub]

I contributed code that allows you to automatically retrieve molecular geometries from the PubChem database - try: geometry_from_pubchem('water'), you can thank me later.

Resources
1. Solutions to Theory of Quantum Information
Sandesh Kalantre, Eddie Schoute, Daochen Wang
Available online, November 2019

Solutions to assignment problems from lecture course CS766/QIC820 Theory of Quantum Information (Fall 2017) at Waterloo by John Watrous. These problems also appear in the book shown on the left.


Stolen from Jon Barron