Quantum Tunneling and Leaping

Hello, I was wondering, what would happen if a cluster of atoms quantum tunneled, and quantum jumped at the same time. I heard that the element anti-hypertritium was able to quantum tunnel. I also learned that if you cool an atom down enough, then hit it with a laser, it would be able to quantum leap. So in theory, if I was to do this procedure on anti-hypertritium, what would happen? Many Thanks, zAk
- zAk (age 18)
Rock Hill, SC, USA

All sorts of quantum systems show tunneling, which means the leaking of a wavefunction through a region in which its kinetic energy is negative. Typical radioactive decays involve tunneling. Many electrical devices require electron tunneling through barriers.

Quantum "leaps" are a fictional process introduced in the early days of proto-quantum theories. In modern quantum mechanics, the quantum state always evolves via a continuous process. There's some mystery involved in the "measurement" aspect of the process, in which we see only a portion of the resulting quantum state, but so far as we know no "leap" ever occurs. If you wish to look up more on this measurement process, a key search term is "decoherence".

Mike W.

(published on 02/08/2013)

I think I actually meant quantum jumping, in my question, instead of quantum leaping, sorry for the confusion.
- zAk (age 18)

Same thing. It's a fictional process. According to the equations we know, that work to extreme accuracy, quantum states change in a continuous way. Maybe some other effects will be discovered some day, but the jumps or leaps that Bohr thought were there back in the day aren't part of the process, despite what people say.

Mike W.

(published on 02/09/2013)

Hello, What would it take to get an object to macro-quantum jump? to get an item, say an apple to get from point A to C without passing through point B? Thanks, zAk
- zAk (age 18)
Rock Hill, SC, USA

So far as we know, all of quantum mechanics is described by an effective field theory. The changes in the quantum state at any place are a smooth function of the current state right near there. If there's a region where the field representing some object is zero, the field for that object can work its way in from the edges of the region, but can't just pop up in the middle. So if there's no "appleness" near C , the apple won't get there without its wave smoothly moving over there from near A. This holds for tunneling processes as well as more classical-like motions.

Mike W.

(published on 02/09/2013)

So, if I wanted the "apple" to get from A to C it would need to be turned into a wave and beamed through point (or obstacle) B and to point C whilst having a part of the "appeliness" in point C using quantum tunneling to get through B. Since a quantum jump cannot occur, would this wave process have the same result (apple at C)? Or am I completely misunderstanding this concept.
- zAk (age 18)
Rock Hill, SC, USA

The apple. like all objects of which we are aware, is already a "wave", i.e. a quantum state. It's one with a rather definite location. You have a lot of familiarity with this type of big quantum object. Your intuition tells you that there's no chance of it getting from A to C if it doesn't pick up kinetic energy to get through barrier B in between. The quantum version of that is simply to say that over apple-size distances apple-size masses have extremely low tunneling rates for even very shallow barriers.

For example, if the apple weighs 100 gm and you want it to displace 10 cm through a barrier of 10^-14 ergs (less than the amount of kinetic energy things pick up from just room temperature jiggling), there's no chance the apple would make it by tunneling in the lifetime of the universe. The little bit of thermal shaking, basically a classical effect, would have a better chance of getting it there, although that's still not to be expected in the lifetime of the universe, much less the apple.

Mike W.

(published on 02/16/2013)