7 papers · 1 filter
Superadditivity of channel capacity through quantum fields
Koji Yamaguchi, Aida Ahmadzadegan, Petar Simidzija +2
Given that any communication is communication through quantum fields, we here study the scenario where a sender, Alice, causes information-carrying disturbances in a quantum field.…
Duality in the dynamics of Unruh-DeWitt detectors in conformally related spacetimes
Masahiro Hotta, Achim Kempf, Eduardo Martín-Martínez +2
We prove a nonperturbative duality concerning the dynamics of harmonic-oscillator-type Unruh-DeWitt detectors in curved spacetimes. Concretely, using the Takagi transformation we s…
A Fundamental Upper Bound for Signal to Noise Ratio of Quantum Detectors
Ryota Katsube, Masahiro Hotta, Koji Yamaguchi
Quantum fluctuations yield inevitable noises in quantum detection. We derive an upper bound of signal to noise ratio for arbitrary quantum detection described by trace-class operat…
Strong Chaos of Fast Scrambling Yields Order: Emergence of Decoupled Quantum Information Capsules
Masahiro Hotta, Koji Yamaguchi
The information loss problem in black hole evaporation is one of fundamental issues. Its resolution requires more profound understanding of information storage mechanism in quantum…
Quantum Information Capsule in Multiple-Qudit Systems and Continuous-Variable Systems
Koji Yamaguchi, Masahiro Hotta
Quantum correlations in an entangled many-body system are capable of storing information. Even when the information is injected by a local unitary operation to the system, the enta…
Quantum Information Capsule and Information Delocalization by Entanglement in Multiple-qubit Systems
Koji Yamaguchi, Naoki Watamura, Masahiro Hotta
Where do entangled multiple-qubit systems store information? For information injected into a qubit, this question is nontrivial and interesting since the entanglement delocalizes t…