232 citations · 1.3k across the 64 of their papers we have counts for
4 papers · 1 filter
Decoherence of anomalously-fluctuating states of finite macroscopic systems
Akira Shimizu, Takayuki Miyadera, Akihisa Ukena
In quantum systems of a macroscopic size V, such as interacting many particles and quantum computers with many qubits, there exist pure states such that fluctuations of some intens…
Fragility of Thermodynamically-Abnormal Ground States of Finite Systems
Takayuki Miyadera, Akira Shimizu
We study a general macroscopic quantum system of a finite size, which will exhibit a symmetry breaking if the system size goes to infinity, when the system interacts with an enviro…
Energies and collapse times of symmetric and symmetry-breaking states of finite systems with a U(1) symmetry
Akira Shimizu, Takayuki Miyadera
We study quantum systems of volume V, which will exhibit the breaking of a U(1) symmetry in the limit of V \to \infty, when V is large but finite. We estimate the energy difference…
Charge superselection rule does not rule out pure states of subsystems to be coherent superpositions of states with different charges
Akira Shimizu, Takayuki Miyadera
We consider a huge quantum system that is subject to the charge superselection rule, which requires that any pure state must be an eigenstate of the total charge. We regard some pa…