Pruet Kalasuwan

Adding control to arbitrary unknown quantum operations

Although quantum computers promise significant advantages, the complexity of quantum algorithms remains a major technological obstacle. We have developed and demonstrated an architecture-independent technique that simplifies adding control qubits to arbitrary quantum operations—a requirement in many quantum algorithms, simulations and metrology. The technique, which is independent of how the operation is done, does not require knowledge of what the operation is, and largely separates the problems of how to implement a quantum operation in the laboratory and how to add a control. Here, we demonstrate an entanglement-based version in a photonic system, realizing a range of different two-qubit gates with high fidelity.

Calculating unknown eigenvalues with a quantum algorithm

Researchers present a photonic demonstration of a full quantum algorithm without knowing the answer in advance. The unknown eigenvalues are truly calculated by the iterative phase estimation algorithm circuit. The demonstrated scheme is essential for practical applications of the phase estimation algorithm, including quantum simulations, quantum metrology and factoring.

Simple scheme for expanding photonic cluster states for quantum information

We show how an entangled cluster state encoded in the polarization of single photons can be straightforwardly expanded by deterministically entangling additional qubits encoded in the path degree of freedom of the constituent photons. This can be achieved using a polarization–path controlled-phase gate. We experimentally demonstrate a practical and stable realization of this approach by using a Sagnac interferometer to entangle a path qubit and polarization qubit on a single photon. We demonstrate precise control over phase of the path qubit to change the measurement basis and experimentally demonstrate properties of measurement-based quantum computing using a two-photon, three-qubit cluster state.

Quantum Information Science with Photons on a Chip

Quantum technologies based on photons will likely require integrated optics architectures for improved performance, miniaturization and scalability. We demonstrate high-fidelity silica-on-silicon integrated optical realizations of key quantum photonic circuits.

Photonic components for Quantum Information Science

Integrated photonics is required to fully exploit the capabilities of Optical Quantum Information science. We demonstrate new components that take full advantage of the integrated architecture; we show quantum interference in MMI couplers and two-particle quantum walks in coupled waveguides.

New photonic components for quantum information science

Optical quantum technologies require new photonic components to exploit integrated architecture. We demonstrate quantum interference in MMI couplers and coupled waveguides that implement two-particle quantum walks, showing unique quantum behaviour.

Quantum information science with photonic chips

Quantum technologies based on photons will likely require integrated optics architectures for improved performance, miniaturization and scalability. We demonstrate high-fidelity silica-on-silicon integrated optical realizations of key quantum photonic circuits and the first integrated quantum algorithm.

Advances in Photonic Quantum Information Science

Quantum technologies based on photons will likely require integrated optics architectures for improved performance, miniaturization and scalability. We demonstrate high-fidelity silica-on-silicon integrated optical realizations of key quantum photonic circuits and the first integrated quantum algorithm.