The quantum internet

Abstract

Quantum networks provide opportunities and challenges across a range of intellectual and technical frontiers, including quantum computation, communication and metrology. The realization of quantum networks composed of many nodes and channels requires new scientific capabilities for generating and characterizing quantum coherence and entanglement. Fundamental to this endeavour are quantum interconnects, which convert quantum states from one physical system to those of another in a reversible manner. Such quantum connectivity in networks can be achieved by the optical interactions of single photons and atoms, allowing the distribution of entanglement across the network and the teleportation of quantum states between nodes.

Non-classical correlations between single photons and phonons from a mechanical oscillator

“…It allows quantum states of matter, such as spin states of atoms [1,2], atomic ensembles [3,4] or solids [5], to be prepared and manipulated by photon counting and, in particular, to be distributed over long distances. Such light-matter interfaces have become crucial to fundamental tests of quantum physics [6] and realizations of quantum networks [7]. Here we report non-classical correlations between single photons and phonons -the quanta of mechanical motion -from a nanomechanical resonator.…”

“…Recent achievements include single-phonon control of a micromechanical resonator by a superconducting flux qubit [16], the generation of quantum entanglement between quadratures of a microwave cavity field and micromechanical motion [20], * This work was published in Nature 530, 313-316 (2016 Interfacing mechanics with optical photons in the quantum regime is highly desirable because it adds important features such as the ability to transfer mechanical excitations over long distances [9,24]. In addition, the available toolbox of single-photon generation and detection allows for remote quantum state control [7]. However, microand nano-mechanical quantum control through single optical photons has not yet been demonstrated.…”

“…Although these experiments were based on the same underlying interactions, they involved homodyne or heterodyne detection of light to access continuous-variable degrees of freedom of a quantum state -specifically, quadrature fluctuations in the mechanical and optical canonical variables. In contrast, the DLCZ scheme uses photon counting, which allows access to discrete quantum variables -here, in form of energy eigenstates (phonons) of the mechanical motion -and thereby enables realistic architectures for entanglement distribution and quantum networking [7].The mechanical system studied here is a microfabricated silicon photonic crystal nanobeam structure (Fig. 1a).…”

“…In addition, the available toolbox of single-photon generation and detection allows for remote quantum state control [7]. However, microand nano-mechanical quantum control through single optical photons has not yet been demonstrated.…”

Physics: Unite to build a quantum Internet

“…One of the greatest challenges for implementing a globally distributed quantum computer or a quantum internet is entangling nodes across the network 8 . Qubits can then be teleported between any pair and processed by local quantum computers.…”