Towards quantum teleportation

Controlling microscopic physical systems has already been demonstrated successfully in numerous experiments, in particular in the field of quantum optics. Current research interest focuses on achieving quantum-mechanical control at the macroscopic scale as well.

Promising systems for this purpose are mechanical oscillators. The EU-funded project 'Optomechanical entanglement and teleportation' (OMENT) was established to demonstrate quantum control of a micrometre-sized mechanical oscillator and use it for a crucial quantum information application: teleportation.

OMENT sought to prepare low-entropy mechanical states such as the ground state of an optomechanical oscillator. Based on this, scientists would create and verify entangled optomechanical states. Such states only appear in quantum mechanics and are the resource in numerous quantum information applications. The created optomechanical entanglement would be used to teleport information.

Novel optomechanical protocols included suggestions on how to implement optomechanical entanglement, teleportation and ultrafast cooling schemes in the pulsed optical regime.

A decisive step in OMENT was to use mechanical oscillators with high Q factors — lower rates of energy losses — as high as 10^7 at low temperatures. Scientists investigated a novel material system based on indium gallium phosphide (InGaP) for membrane mechanical resonators. This allowed easy and monolithic integration of stacked membranes that promise a high single-photon coupling strength.

Major effort was devoted to achieve two stable cavity-optomechanics systems at low temperatures in a dilution refrigerator and a helium flow cryostat.

Quantum-controlled mechanical oscillators extend the physical regimes of information processing where quantum effects are significant to macroscopic scales. Furthermore, they also allow designing ultra-sensitive quantum-limited measurement devices.

Project advances significantly contributed to realising a set of experimental parameters that should eventually allow observing optomechanical quantum entanglement between a laser field and a micromechanical oscillator. All project findings were published in peer-reviewed journals.