#### Filter Results:

- Full text PDF available (64)

#### Publication Year

1993

2017

- This year (1)
- Last 5 years (17)
- Last 10 years (38)

#### Publication Type

#### Co-author

#### Journals and Conferences

#### Key Phrases

#### Method

Learn More

All real world quantum systems interact with their surrounding environment to a greater or lesser extent. Such systems are said to be open. No matter how weak the coupling that prevents the system from being isolated, the evolution of an open quantum system is eventually plagued by nonunitary features like decoherence and dissipation [1]. Quantum… (More)

- Lorenza Viola, Seth Lloyd
- 1998

The dynamics of a decohering two-level system driven by a suitable control Hamiltonian is studied. The control procedure is implemented as a sequence of radiofrequency pulses that repetitively flip the state of the system, a technique that can be termed quantum “bang-bang” control after its classical analog. Decoherence introduced by the system’s… (More)

- Lorenza Viola, Emanuel Knill
- Physical review letters
- 2003

We propose a general procedure for implementing dynamical decoupling of quantum systems without requiring arbitrarily strong, impulsive control actions. This is accomplished by designing continuous decoupling propagators according to Eulerian paths in the decoupling group for the system. Such Eulerian decoupling schemes offer two important advantages over… (More)

- Evan M. Fortunato, Lorenza Viola, +4 authors David G. Cory

Evan M. Fortunato,1 Lorenza Viola,2, Marco A. Pravia,1 Emanuel Knill,2 Raymond Laflamme,3 Timothy F. Havel,1 and David G. Cory1 1 Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 2 Los Alamos National Laboratory, Mail Stop B256, Los Alamos, NM 87545 3 Department of Physics, University of Waterloo, Waterloo, ON… (More)

- Francesco Ticozzi, Lorenza Viola
- IEEE Trans. Automat. Contr.
- 2008

We characterize the dynamical behavior of continuous-time, Markovian quantum systems with respect to a subsystem of interest. Markovian dynamics describes a wide class of open quantum systems of relevance to quantum information processing, subsystem encodings offering a general pathway to faithfully represent quantum information. We provide explicit… (More)

- R Laflamme, E Knill, +11 authors L Viola
- 2001

2 Principles of Liquid-State NMR QIP 7 2.1 Realizing Qubits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2 One Qubit Gates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.3 Two Qubit Gates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.4 Turning off… (More)

- L Viola, E M Fortunato, M A Pravia, E Knill, R Laflamme, D G Cory
- Science
- 2001

We demonstrate the protection of one bit of quantum information against all collective noise in three nuclear spins. Because no subspace of states offers this protection, the quantum bit was encoded in a proper noiseless subsystem. We therefore realize a general and efficient method for protecting quantum information. Robustness was verified for a full set… (More)

- Lorenza Viola, Emanuel Knill
- Physical review letters
- 2005

We present a general control-theoretic framework for constructing and analyzing random decoupling schemes, applicable to quantum dynamical control of arbitrary finite-dimensional composite systems. The basic idea is to design the control propagator according to a random rather than deterministic path on a group. We characterize the performance of random… (More)

We show that if one can perform a restricted set of fast manipulations on a quantum system, one can implement a large class of dynamical evolutions by effectively removing or introducing selected Hamiltonians. The procedure can be used to achieve universal noise-tolerant control based on purely unitary open-loop transformations of the dynamics. As a result,… (More)

- Kaveh Khodjasteh, Lorenza Viola
- Physical review letters
- 2009

Scalable quantum computation in realistic devices requires that precise control can be implemented efficiently in the presence of decoherence and operational errors. We propose a general constructive procedure for designing robust unitary gates on an open quantum system without encoding or measurement overhead. Our results allow for a low-level error… (More)