Linear optics with photon counting is a prominent candidate for practical quantum computing. The protocol by Knill, Laflamme, and Milburn [2001, Nature (London) 409, 46] explicitly demonstrates that… Expand

We describe in detail the theory underpinning the measurement of density matrices of a pair of quantum two-level systems ~‘‘qubits’’ !. Our particular emphasis is on qubits realized by the two… Expand

The key element of this gate is nondemolition detectors that use a weak cross-Kerr nonlinearity effect to conditionally generate a phase shift on a coherent probe if a photon is present in the signal mode.Expand

We show that quantum computation circuits using coherent states as the logical qubits can be constructed from simple linear networks, conditional photon measurements, and "small" coherent… Expand

The basic aspects of quantum error correction and fault-tolerance are examined largely through detailed examples, which are more relevant to experimentalists today and in the near future.Expand

This work presents a new route for distributed optical QIP, based on generalized quantum non-demolition measurements, providing a unified approach for quantum communication and computing.Expand

A quantum repeater protocol for long-distance quantum communication that creates entanglement between qubits at intermediate stations of the channel by using a weak dispersive light-matter interaction and distributing the outgoing bright coherent-light pulses among the stations.Expand

A deterministic process—coherent photon conversion (CPC)— is introduced that provides a new way to generate and process complex, multiquanta states for photonic quantum information applications and is not restricted to optical systems but could also be implemented in optomechanical, electromechanical and superconducting systems with extremely strong intrinsic nonlinearities.Expand

Maximally entangled mixed states are those states that, for a given mixedness, achieve the greatest possible entanglement. For two-qubit systems and for various combinations of entanglement and… Expand

Random-bit generators (RBGs) are key components of a variety of information processing applications ranging from simulations to cryptography. In particular, cryptographic systems require 'strong'… Expand