Linearly positive histories: Probabilities for a robust family of sequences of quantum events.

Non-negative probabilities that obey the sum rules may be assigned to a much wider family of sets of histories than decohering histories. The resulting linearly positive histories avoid the highly restrictive decoherence conditions and yet give the same probabilities when those conditions apply. Thus linearly positive histories are a broad extension of decohering histories. Moreover, the resulting theory is manifestly time-reversal invariant.

满足求和规则的非负概率可以被赋予比退相干历史更广泛的一系列历史集合。由此产生的线性正历史避开了高度受限的退相干条件，并且当这些条件适用时给出相同的概率。因此，线性正历史是对退相干历史的广泛扩展。此外，由此产生的理论显然是时间反演不变的。