Event Details

Quantum Interference between Light Sources Separated by 150 Million Kilometres

According to quantum theory, when two identical single photons simultaneously enter a beam splitter, quantum interference forces both of them to bunch together and always exit from the same beamsplitter port. Subsequent variations of the experiment have tested a variety of settings to show that photons from distant sources can show quantum interference. Now, researchers from China has harnessed sunlight to demonstrate quantum interference between photons generated 150 million km apart, setting the stage for quantum optics experiments on astronomical scales. The team went on to generate entangled states between photons from the two disparate sources and demonstrated that such states clearly violated a Bell inequality.