- #1
James MC
- 174
- 0
Hello,
The quantum zeno effect is well understood and experimentally confirmed as regards polarization measurements (as discussed here). It's the quantum analogue of "the watched pot never boils" as it allows "continuous" measurement to inhibit certain state evolutions.
Does the effect (in principle) enable one to keep a particle confined to a particular spot simply via "continuous" position measurements?
Consider double slit experiment, we fire the electron towards the slits, but our goal is to prevent the electron from reaching the slits by continuously measuring the electron's position - is this in principle possible?
It seems that it is: "shooting" the electron out towards the slits suggests that position amplitude for electron rises (from zero) closer to the slit. So you can imagine that we measure position of electron just after it leaves the electron gun. High amp close to gun, low amp close to slits (at the "right after shooting" instant), so electron (at that instant) probably will collapse close to gun, far from slits. The quicker we make that measurement, the less chance we get collapse to region close to slits, far from gun. So now imagine that we make "continuous" position measurements of electron right as it leaves gun. In the limit there is no chance that the electron can move from point of measurement...
This seems quite odd (what happened to all that velocity??), but reasoning seems analogous to well-understood polarization case.
Would appreciate if someone could help enlighten me here. Thanks!
The quantum zeno effect is well understood and experimentally confirmed as regards polarization measurements (as discussed here). It's the quantum analogue of "the watched pot never boils" as it allows "continuous" measurement to inhibit certain state evolutions.
Does the effect (in principle) enable one to keep a particle confined to a particular spot simply via "continuous" position measurements?
Consider double slit experiment, we fire the electron towards the slits, but our goal is to prevent the electron from reaching the slits by continuously measuring the electron's position - is this in principle possible?
It seems that it is: "shooting" the electron out towards the slits suggests that position amplitude for electron rises (from zero) closer to the slit. So you can imagine that we measure position of electron just after it leaves the electron gun. High amp close to gun, low amp close to slits (at the "right after shooting" instant), so electron (at that instant) probably will collapse close to gun, far from slits. The quicker we make that measurement, the less chance we get collapse to region close to slits, far from gun. So now imagine that we make "continuous" position measurements of electron right as it leaves gun. In the limit there is no chance that the electron can move from point of measurement...
This seems quite odd (what happened to all that velocity??), but reasoning seems analogous to well-understood polarization case.
Would appreciate if someone could help enlighten me here. Thanks!