Building Quantum Computers

Prof. Bill CoishDepartment of Physics

McGill UniversityMontreal, Canada

ETSI-IQC Workshop (Toronto) 2016 September 20

“We do not see the need to upgrade current systems as urgent, though a transition to post-quantum public key cryptography will be necessary.”

https://www.cesg.gov.uk/content/files/protected_files/guidance_files/Quantum%20Key%20Distrubution%20-%20CESG%20White%20Paper.pdf

GCHQ (UK) CESG White Paper

Ars Technica (August 2015):

“NSA preps quantum-resistant algorithms to head off crypto-apocalypse”

GCHQ (UK) CESG White Paper (February 2016)

http://arstechnica.com/security/2015/08/nsa-preps-quantum-resistant-algorithms-to-head-off-crypto-apocolypse/

"Our ultimate goal is to provide cost effective security against a potential quantum computer,"

NSA statement posted online:

Superconducting devices

Trapped ions/atoms

Spins

Debnath et al. “Demonstration of a small programmable quantum computer with atomic qubits”, Nature 536, 63 (August 2016)

https://quantumexperience.ng.bluemix.net/

Veldhorst et al. “A Two-qubit Logic Gate in Silicon”, Nature 526, 410 (October 2015)

Maurand et al. “A CMOS Silicon Spin Qubit”, ArXiv.org:1605.07599 (May 2016)

Avogadro crystal: Highly pure 28Si

How long can quantum states live?

Isolated nuclear spins in highly pure 28Si behave almost like they are in 'vacuum'

Sayeedi et al., Science (Nov. 2013)

World record lifetime for quantum coherence:

http://www.economist.com/technology-quarterly/2016-03-12/after-moores-law

C. Monroe(atomic qubits)

R. Schoelkopf(supercond. qubits)

M. Lukin(spin qubits)

Entanglement at 1.3 km for spins in diamond!

NYTimes.com (October 21, 2015)

http://qutech.nl/hanson-lab/loophole-free-bell-test/

M. Ahsan, R. van Meter, and J. Kim“Designing a Million-Qubit Quantum Computer using a Resource Performance Simulator”ACM JETCS 12, 39 (December 2015)

“...Using this tool, we investigate a vast design space for implementing key building blocks of Shor’s algorithm to factor a 1,024-bit number with a baseline budget of 1.5 million qubits. We show that a trapped-ion quantum computer designed with twice as many qubits and one-tenth of the baseline infidelity of the communication channel can factor a 2,048-bit integer in less than 5 months.”