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Cover story
PROF. Q*BIT'S QUIRKY QUANTUM CHAT
As an inhabitant of the quantum world, it is not easy for me to report on my everyday life. Things are so different around here. They follow their own rules, the rules of quantum physics, dominated by a certain fuzziness. For example, if my assistant asks me where I will be at three o'clock sharp this afternoon, I answer: “In the office and in the lab.” Of course he wants to know: “But where? Where exactly?” And I reply: “Well, in both places!” For humans and other non-quants, this might be hard to imagine. But I can assure you: for me, this has often proven to be extremely useful.
In the quantum world, we are also bothering with questions of identity. It’s always the same: you would like me to tell you whether I am a particle or a wave. I shrug my shoulders, sigh briefly and say: “What do you think? I’m both. This is called the wave-particle duality.“
We know no moods in the quantum world. We’re in states, and we jump back and forth between them. These are veritable quantum leaps. For example, when I dance and whirl in a circle, my spin – this is my own angular momentum – obeys the rules of quantum physics. I can then turn around my axis only to the left or to the right. I jump back and forth between the two directions. But since I also possess the properties of a wave, my states can overlap. That’s what we call superposition, a mixture of the two spins. I turn to the left – and at the same time to the right. It’s unimaginable, actually, but that’s how it works with us quanta.
We know no moods in the quantum world. We’re in states, and we jump back and forth between them. These are veritable quantum leaps. For example, when I dance and whirl in a circle, my spin – this is my own angular momentum – obeys the rules of quantum physics. I can then turn around my axis only to the left or to the right. I jump back and forth between the two directions. But since I also possess the properties of a wave, my states can overlap. That’s what we call superposition, a mixture of the two spins. I turn to the left – and at the same time to the right. It’s unimaginable, actually, but that’s how it works with us quanta.
Relationships in the quantum world are very special. And that’s because of the phenomenon of entanglement. Proximity and distance are therefore not mutually exclusive with us. My wife and I, for example, we have entangled. We are connected to each other as with an invisible bond, no matter how far away we are from each other. And when we change our properties, we don’t do it alone, we change them both at the same time. That’s the way it is with us quanta. However, I have been told that even in the human world, intimate relationships exist over great distances – without any entanglement.Arndt Reuning
Images: Forschungszentrum Jülich, Graphic: SeitenPlan GmbH