Quantum Attacks on Bitcoin, and How to Protect Against Them
- Divesh Aggarwal, G. Brennen, Troy Lee, M. Santha, M. Tomamichel
- 27 October 2017
Computer Science, Mathematics
It is found that the proof-of-work used by Bitcoin is relatively resistant to substantial speedup by quantum computers in the next 10 years, mainly because specialized ASIC miners are extremely fast compared to the estimated clock speed of near-term quantum computers.
A toolbox for lattice-spin models with polar molecules
- A. Micheli, G. Brennen, P. Zoller
- 23 December 2005
There is growing interest in states of matter with topological order. These are characterized by highly stable ground states robust to perturbations that preserve the topology, and which support…
QUANTUM LOGIC GATES IN OPTICAL LATTICES
- G. Brennen, C. Caves, P. Jessen, I. Deutsch
- 6 June 1998
We propose a new system for implementing quantum logic gates: neutral atoms trapped in a very far-off-resonance optical lattice. Pairs of atoms are made to occupy the same well by varying the…
Entanglement dynamics in one-dimensional quantum cellular automata
- G. Brennen, Jamie E. Williams
- 6 June 2003
Several proposed schemes for the physical realization of a quantum computer consist of qubits arranged in a cellular array. In the quantum circuit model of quantum computation, an often complex…
Quantum magnetomechanics: ultrahigh-Q-levitated mechanical oscillators.
- M. Cirio, G. Brennen, J. Twamley
- 22 December 2011
Physical Review Letters
This work examines a magneto-meso-mechanical quantum system that consists of a 3D arrangement of miniature superconducting loops which is stably levitated in a static inhomogeneous magnetic field and inductively coupling this levitating object to a nearby driven flux qubit may permit the generation of macroscopic entangled motional states of multiple clusters.
Canonical decompositions of n-qubit quantum computations and concurrence
- S. Bullock, G. Brennen
- 12 September 2003
The two-qubit canonical decomposition SU(4)=[SU(2)⊗SU(2)]Δ[SU(2)⊗SU(2)] writes any two-qubit unitary operator as a composition of a local unitary, a relative phasing of Bell states, and a second…
Asymptotically optimal quantum circuits for d-level systems.
- S. Bullock, D. O’Leary, G. Brennen
- 14 October 2004
Physical Review Letters
Both a lower bound and a constructive upper bound on the number of two-qudit gates result, proving a sharp asymptotic of theta(d(2n)) gates, which closes the complexity question for all d-level systems (d finite).
Efficient circuits for exact-universal computationwith qudits
- G. Brennen, S. Bullock, D. O’Leary
- 22 September 2005
Quantum information & computation
It is shown that controlled two-qudit gates can be implemented without ancillas and it is proved that the gate library containing arbitrary local unitaries and one two- qudit gate, CINC, is exact-universal.
Room-temperature spontaneous superradiance from single diamond nanocrystals
- C. Bradac, M. Johnsson, T. Volz
- 10 August 2016
The results pave the way towards a systematic study of SR in a well-controlled, solid-state quantum system at room temperature from single, highly luminescent diamond nanocrystals with spatial dimensions much smaller than the wavelength of light.
Quantum walks with memory provided by recycled coins and a memory of the coin-flip history
- P. Rohde, G. Brennen, A. Gilchrist
- 2 May 2013
Quantum walks have emerged as an interesting approach to quantum information processing, exhibiting many unique properties compared to the analogous classical random walk. Here we introduce a model…