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Abstract |
In the quantum world, measurements inevitably affect the state of a system, via wavefunction collapse. This
means that the dynamics of a system which is continually being monitored by an observer is fundamentally
different from the dynamics of a closed system. In particular, for a spatially extended system, local
measurements of the degrees of freedom can “compete" with chaotic dynamics: while chaotic dynamics
tends to produce complex, entangled quantum wavefunctions, local measurements tend to collapse the
wavefunction into something simpler. I will describe how this leads to a dynamical phase transition between a
weak monitoring phase, where the state is complex and entangled, and a strong monitoring phase, where the
state is simple and “classical”. I will sketch the relevance of this transition to the classical simulation of
quantum dynamics, and some theoretical approaches to understanding the transition. |
