14 citations · 64 across the 11 of their papers we have counts for
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Geometric phase of a two-level system in a dissipative environment
Kazuo Fujikawa, Ming-Guang Hu
The geometric (Berry) phase of a two-level system in a dissipative environment is analyzed by using the second-quantized formulation, which provides a unified and gauge-invariant t…
Adiabatic approximation in the second quantized formulation
Kazuo Fujikawa
Recently there have been some controversies about the criterion of the adiabatic approximation. It is shown that an approximate diagonalization of the effective Hamiltonian in the…
On the separability criterion for continuous variable systems
Kazuo Fujikawa
We present an elementary and explicit proof of the separability criterion for continuous variable two-party Gaussian systems. Our proof is based on an elementary formulation of unc…
Geometric phases for mixed states and decoherence
Kazuo Fujikawa
The gauge invariance of geometric phases for mixed states is analyzed by using the hidden local gauge symmetry which arises from the arbitrariness of the choice of the basis set de…
Geometric phases, gauge symmetries and ray representation
Kazuo Fujikawa
The conventional formulation of the non-adiabatic (Aharonov-Anandan) phase is based on the equivalence class which is not a symmetry of the Schrödinger…
Topological properties of Berry's phase
Kazuo Fujikawa
By using a second quantized formulation of level crossing, which does not assume adiabatic approximation, a convenient formula for geometric terms including off-diagonal terms is d…