| Memoryless processes are ubiquitous in nature, in contrast with the mathematics of open systems theory, which states that non-Markovian processes should be the norm. This discrepancy is usually addressed by subjectively making the environment forgetful. In my talk, I will describe how when a quantum stochastic process has dynamics given by an approximate unitary design, a large deviation bound on the size of non-Markovian memory is implied. I will also describe an example of this result by means of an efficient construction of an approximate unitary circuit design using two-qubit interactions only, showing how seemingly simple systems can readily become forgetful. |
