Virtual distillation with noise dilution

Virtual distillation is an error-mitigation technique that reduces quantum-computation errors without assuming the noise type. In scenarios where user of a quantum circuit required to additionally employ peripherals, such as delay lines, introduce excess noise, we find performance can be improved if peripheral, whenever possible, split across entire circuit, is, when channel uniformly distributed in layers within circuit. We show under multiqubit loss and Pauli channels, respectively, for given overall error rate, average mitigation improves monotonically noisy peripheral (diluted) into more layers, with each layer sandwiched between subcircuits are sufficiently deep behave 2-designs. For both analytical numerical evidence second-order generally sufficient (near-)optimal mitigation. propose application these findings designing quantum-computing cluster houses realistic intermediate-scale circuits may shallow depth, measurement detectors limited lines necessary queue output qubits from multiple circuits.