It is a known fact that due to space-time relativity the time flows slower when you move faster and that the time also slows down the moment you get closer to a center of gravity. This is called time dilation and it has been measures in GPS satellites or when people flew with the airplanes and now even in the lab.
For example, at 20 000 km altitude, where the GPS satellites are, they fly with about 3.8 km/s and time should slow down due to this speed, but because they are so far away from the center of gravity, Earth, it means that it will flow faster. With about 8 microseconds faster, that is.
This is why the GPS satellites have atomic clocks which are then reset based on the clocks on Earth. A 8 microsecond faster time reported by the satellites means that you will be sent by the GPS receiver a few miles away from your destination. Not good at all.
So, now that we know that this effect is real, measured over and over again, how could we make time slow down in the lab?
Ars Technica reports that researchers from Germany, a whole bunch of them, accelerated Li+ ions to 40% of the speed of light and then using lasers and Doppler effect they were able to calculate by how much did the time slow down for those ions.
Well, that is pretty cool. The study can be read here at Physical Review Letters, 2014, DOI: 10.1103/PhysRevLett.113.120405