40 citations · 250 across the 28 of their papers we have counts for
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3 papers · 1 filter
math.AG2017★ 2 cited
On a theorem by Kippenhahn
Stephan Weis
Kippenhahn discovered a real algebraic plane curve whose convex hull is the numerical range of a matrix. The correctness of this theorem was called into question when Chien and Nak…
math-ph2017★ 3 cited
A variation principle for ground spaces
Stephan Weis
The ground spaces of a vector space of hermitian matrices, partially ordered by inclusion, form a lattice constructible from top to bottom in terms of intersections of maximal grou…
math-ph2017★ 5 cited
A new signature of quantum phase transitions from the numerical range
Ilya M. Spitkovsky, Stephan Weis
The ground state energy of a finite-dimensional one-parameter Hamiltonian and the continuity of a maximum-entropy inference map are discussed in the context of quantum critical phe…