%0 Journal Article
%T Necessity of Eigenstate Thermalization
%A Giacomo De Palma
%A Alessio Serafini
%A Vittorio Giovannetti
%A Marcus Cramer
%J Physics
%D 2015
%I arXiv
%R 10.1103/PhysRevLett.115.220401
%X Under the Eigenstate Thermalization Hypothesis (ETH), quantum-quenched systems equilibrate towards canonical, thermal ensembles. While at first glance the ETH might seem a very strong hypothesis, we show that it is indeed not only sufficient but also necessary for thermalization. More specifically, we consider systems coupled to baths with well-defined macroscopic temperature and show that whenever all product states thermalize then the ETH must hold. Our result definitively settles the question of determining whether a quantum system has a thermal behaviour, reducing it to checking whether its Hamiltonian satisfies the ETH.
%U http://arxiv.org/abs/1506.07265v2