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The idea that light can grab hold of objects may sound like science fiction, but optical tweezers that hold particles at a laser focus are widely used today. An even more fictional-sounding concept is the tractor beam – a beam of light or sound that can pull an object towards it. Over the past three years or so, physicists have shown that tractor beams are theoretically possible – and there has been a flurry of activity in the lab to try to build one.