A significant advancement in quantum computing has been achieved with the use of a single laser beam, marking a notable progression in Austria. This breakthrough enables intricate quantum calculations, propelling the development of ultra-fast computers.

Creating quantum computers challenging

Quantum computers offer superior performance for specific tasks such as quantum physics modeling, machine learning and cryptography. However, constructing large-scale universal quantum computers presents significant challenges for engineers.

It is important to note that quantum computing hinges on exploiting peculiar quantum phenomena such as superposition and entanglement. Unlike classical computers quantum computers utilize superposition, allowing particles to exist in multiple states simultaneously. Additionally, quantum particles can display entanglement, where their states are intertwined regardless of distance.

Experimental quantum computers predominantly utilize individual photons as carriers of quantum information. These photons are encoded into various properties such as polarization direction or spatial mode. Manipulating these quantum states of photons enables sampling from probability distributions that pose computational challenges for classical computers.

The University of Vienna researchers’ breakthrough addresses the challenge of handling increasing numbers of photons for complex calculations. Their work is crucial due to the overwhelming demand for experimental resources like optical circuits, detectors, and sources in standard computing architecture.

New approach uses quantum dot as photon emitter

Detailed in Science Advances, the novel method utilizes a state-of-the-art quantum dot as a top-notch single photon emitter. Similar to a single atom, the quantum dot emits uniform photons individually upon laser pulse activation. Instead of encoding quantum data into various photon properties, the researchers opt for using the photons’ timing for information transmission.

The researchers manipulated laser pulses to create sequences of up to eight single photons, each separated by precise intervals along one laser beam path. These photon sequences were then passed through a programmable interferometer circuit, allowing independent manipulation and interference of each time window while maintaining the same spatial mode.

A crucial element enabling this capability is a rapid electro-optic modulator that can alter the interferometer’s reflectivity every 100 nanoseconds. This high speed allows individual photons to undergo distinct controlled operations, interfering with various time bins at the output.