617 citations · 2.9k across the 72 of their papers we have counts for
6 papers · 1 filter
Fundamental limitations in the purifications of tensor networks
G. De las Cuevas, T. S. Cubitt, J. I. Cirac +2
We show a fundamental limitation in the description of quantum many-body mixed states with tensor networks in purification form. Namely, we show that there exist mixed states which…
Size-Driven Quantum Phase Transitions
Johannes Bausch, Toby S. Cubitt, Angelo Lucia +2
Can the properties of the thermodynamic limit of a many-body quantum system be extrapolated by analysing a sequence of finite-size cases? We present a model for which such an appro…
Area law for fixed points of rapidly mixing dissipative quantum systems
Fernando G. S. L. Brandao, Toby S. Cubitt, Angelo Lucia +2
We prove an area law with a logarithmic correction for the mutual information for fixed points of local dissipative quantum system satisfying a rapid mixing condition, under either…
Quantum reverse hypercontractivity
Toby Cubitt, Michael Kastoryano, Ashley Montanaro +1
We develop reverse versions of hypercontractive inequalities for quantum channels. By generalizing classical techniques, we prove a reverse hypercontractive inequality for tensor p…
Undecidability of the Spectral Gap (full version)
Toby Cubitt, David Perez-Garcia, Michael M. Wolf
We show that the spectral gap problem is undecidable. Specifically, we construct families of translationally-invariant, nearest-neighbour Hamiltonians on a 2D square lattice of d-l…
Undecidability of the Spectral Gap (short version)
Toby Cubitt, David Perez-Garcia, Michael M. Wolf
The spectral gap - the energy difference between the ground state and first excited state - is central to quantum many-body physics. Many challenging open problems, such as the Hal…