Adversarial hypothesis testing and a quantum stein's lemma for restricted measurements
Adversarial hypothesis testing and a quantum stein's lemma for restricted measurements
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对抗性假设检验和受限测量的量子斯坦引理
DOI:
10.1145/2554797.2554816
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发表时间:
2014
期刊:
影响因子:
--
通讯作者:
Brandão F
中科院分区:
文献类型:
--
作者:
Brandão F
Recall the classical hypothesis testing setting with two convex sets of probability distributionsPandQ. One receives eitherni.i.d. samples from a distributionp∈Por from a distributionq∈Qand wants to decide from which set the points were sampled. It is known that the optimal exponential rate at which errors decrease can be achieved by a simple maximum-likelihood ratio test which does not depend onporq, but only on the setsPandQ.We consider an adaptive generalization of this model where the choice ofp∈Pandq∈Qcan change in each sample in some way that depends arbitrarily on the previous samples. In other words, in thekth round, an adversary, having observed all the previous samples in rounds 1, ...,κ-1, choosespκ∈Pandqκ∈Q, with the goal of confusing the hypothesis test. We prove that even in this case, the optimal exponential error rate can be achieved by a simple maximum-likelihood test that depends only onPandQ.We then show that the adversarial model has applications in hypothesis testing forquantum statesusing restricted measurements. For example, it can be used to study the problem of distinguishing entangled states from the set of all separable states using only measurements that can be implemented with local operations and classical communication (LOCC). The basic idea is that in our setup, the deleterious effects of entanglement can be simulated by an adaptive classical adversary.We prove a quantum Stein's Lemma in this setting: In many circumstances, the optimal hypothesis testing rate is equal to an appropriate notion of quantum relative entropy between two states. In particular, our arguments yield an alternate proof of Li and Winter's recent strengthening of strong subadditivity for quantum relative entropy.