I am interested in quantum control problems concerning continuous quantum measurements in the presence of feedback. I've also worked, in the past, on quantum information theory with applications to certain models of black holes.
Why does the act of measuring a quantum system disturb it? As far as the axioms of quantum mechanics go, quantum measurement stands out as the only irreversible and discontinuous process that quantum states undergo. This is not always the case, however, as some quantum measurements can be designed to disturb quantum states only very weakly. It has already been shown that a rapid succession of such weak measurements can decompose any general quantum measurement into a continuous stochastic process using a feedback loop. Can these loops be implemented experimentally? Some physical systems, such as superconducting qubits, cannot be measured directly and have slow read-out times. In these cases, the measurement can be performed via a stream of probes. Which general measurements can be performed this way?