1 citations · 1 across the 2 of their papers we have counts for
7 papers
Spectral mapping theorem of an abstract non-unitary quantum walk
Keisuke Asahara, Daiju Funakawa, Etsuo Segawa +2
This paper continues the previous work (Quantum Inf. Process (2019)) by two authors of the present paper about a spectral mapping property of chiral symmetric unitary operators. In…
The Witten Index for One-dimensional Non-unitary Quantum Walks with Gapless Time-evolution
Keisuke Asahara, Daiju Funakawa, Motoki Seki +1
Recent developments in the index theory of discrete-time quantum walks allow us to assign a certain well-defined supersymmetric index to a pair of a unitary time-evolution and…
Time operators for continuous-time and discrete-time quantum walks
Daiju Funakawa, Yasumichi Matsuzawa, Akito Suzuki +2
We construct concrete examples of time operators for both continuous and discrete-time homogeneous quantum walks, and we determine their deficiency indices and spectra. For a discr…
Spectral analysis of an abstract pair interaction model
Keisuke Asahara, Daiju Funakawa
We consider an abstract pair-interaction model in quantum field theory with a coupling constant and analyze the Hamiltonian of the model. In the massive c…
Localization for a one-dimensional split-step quantum walk with bound states robust against perturbations
Toru Fuda, Daiju Funakawa, Akito Suzuki
For given two unitary and self-adjoint operators on a Hilbert space, a spectral mapping theorem was proved in \cite{HiSeSu}. In this paper, as an application of the spectral mappin…
Weak limit theorem for a one-dimensional split-step quantum walk
Toru Fuda, Daiju Funakawa, Akito Suzuki
This paper proves a weak limit theorem for a one-dimensional split-step quantum walk and investigates the limit density function. In the density function, the difference between tw…