Hexbyte – Tech News – Ars Technica | Qubits can sync if they have more than two possible values

Hexbyte – Tech News – Ars Technica |

Probability, probably —

A quantum system must have more than two states to synchronize an oscillation.


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Pendulums only provide a limited model for quantum oscillations.

Here’s something you might be familiar with: a performance ends, the audience begins to applaud, and the sound becomes thunderous and continuous. But in your immediate neighborhood, everyone seems to be clapping at the same moment. 

This synchronization is common in the classical world. Attach a few grandfather clocks to a wall and over the course of the day, their pendulums will start to swing in sync. In things like pendulums, the oscillators are not perfect—they lose energy over time. That energy is transmitted through vibrations to neighboring pendulums, where it is absorbed. The mutual emission and absorption of vibrations slowly brings the two pendulums into sync with each other.

Does synchronization work in a quantum system and, if so, how? This is the question a pair of researchers from Switzerland set out to answer.

Hexbyte – Tech News – Ars Technica | Happy swinging

Why does synchronization work in the first place? Well, an oscillator, like a swing, has a frequency that is given by its construction: the mass and length of the rope set a preferred frequency. Phase is also a property of an oscillator. The phase describes where in an oscillation the swing is. So as the swing swings, the frequency stays constant and the amplitude of the oscillation stays constant, but the phase constantly changes. 

Synchronization works because a swing has no preferred phase. Essentially, if I set a swing going now, it will have some phase. I could also set the swing going a bit later, and it would have a different phase. The swing doesn’t care. 

Two swings on the same cross bar will exchange energy. When a swing absorbs energy, it speeds up slightly so the phase advances a bit more than expected. When it emits energy, it slows down. When the two swings are out of phase, the swing that is behind will absorb energy from its partner. This slows the swing that is ahead and speeds the swing that is behind until they are in sync. Once in sync, every time a swing gets a little ahead, it gives up some energy and the other swing gets a little boost to hold them together.

Hexbyte – Tech News – Ars Technica | Spinning out of control

If we add a dash of quantum mechanics, things get more

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