Key Points
- Scientists have a new, more efficient way to create multiple photons for quantum computers.
- The technique uses “quantum dots,” which are tiny semiconductor crystals that emit light.
- It avoids the need for expensive and inefficient electronic switches used in older methods.
- The new method uses precisely timed laser pulses to control the photons directly.
A team of physicists has developed a new, more elegant way to generate particles of light for quantum computing. The breakthrough uses tiny semiconductor crystals called “quantum dots” to create multiple photons at once, overcoming a major hurdle in building powerful quantum technologies.
Quantum dots are a promising source for generating single photons on demand, which are the building blocks of quantum computers. The problem is that every quantum dot is slightly different and produces a slightly different color of light, so you can’t just use a bunch of them together to create a multi-photon state.
The old method involved using a single quantum dot and then splitting its light using expensive, custom-built electronic switches. This approach was not only costly but also inefficient, as it introduced unwanted “noise” into the system.
The new technique, published in npj Quantum Information and developed by an international team of researchers, gets around this problem entirely. Instead of using electronic switches, they use a purely optical method. By carefully timing different laser pulses, they can directly trigger the quantum dot to release a stream of photons with specific properties.
This all-optical approach is a big step forward because it moves the complexity away from the expensive and “lossy” electronics and puts it into the much more controllable optical setup.
The researchers say the technique is more practical for real-world applications and has immediate uses in things like secure quantum communication, where it could allow for multiple secure conversations at the same time.
