Photonic Quantum Computers

Photonic Quantum Computers

This PennyLane tutorial is an accessible introduction to photonic quantum computers, which use particles of light as their information carriers and operate on a fundamentally different model from qubit-based hardware. It explains the continuous-variable picture of quantum optics, where information is encoded in the quantum states of light modes (qumodes), such as the amplitude and phase quadratures of the electromagnetic field, rather than in two-level qubits, and introduces the key states and operations: coherent and squeezed states, beamsplitters and phase shifters that implement linear-optical transformations, and homodyne and photon-number measurements. The tutorial discusses how photonic platforms achieve room-temperature operation and natural compatibility with communication networks, the challenges of implementing nonlinear (non-Gaussian) operations, and how measurement-based and Gaussian-Boson-Sampling approaches fit in. It connects these physical concepts to how photonic devices are modeled and programmed. By explaining the optics and the continuous-variable formalism from the ground up, the tutorial gives readers a clear understanding of how photonic quantum computers work and how this paradigm differs from the gate-based qubit model, a valuable broadening of the hardware landscape.

Run it

pip install -r requirements.txt
python demo.py

Source and license

Imported from demonstrations_v2/tutorial_photonics/demo.py in PennyLaneAI/demos at c52c0abeb5122218aa96b38eea848864cce7323f, under the Apache License 2.0. Original authors: Xanadu and the PennyLane community. The upstream LICENSE is included alongside this example.