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The effect of a local instantaneous quantum dynamical process (QDP), either unitary or non-unitary,
on the quantum state transfer through a unitary Hamiltonian evolution is investigated for both
integrable and non-integrable dynamics. There are interference effects of the quantum state
propagation and the QDP signal propagation. The state transfer fidelity is small for further sites,
from the site where the information is coded, indicating a finite speed for the propagation of the

We obtain continuity bounds for basic information characteristics of quantum channels depending on
their input dimension (if it is finite) and on the input energy bound (if the input dimension is
infinite). We pay special attention to the case in which a multimode quantum oscillator is an input
system. First, we prove continuity bounds for the output conditional mutual information for a single

The partial information decomposition (PID) is perhaps the leading proposal for resolving
information shared between a set of sources and a target into redundant, synergistic, and unique
constituents. Unfortunately, the PID framework has been hindered by a lack of a generally
agreed-upon, multivariate method of quantifying the constituents. Here, we take a step toward
rectifying this by developing a decomposition based on a new method that quantifies unique

Author(s): Anindita Bera, Shiladitya Mal, Aditi Sen(De), and Ujjwal Sen
We investigate sharing of bipartite entanglement in a scenario where half of an entangled pair is possessed and projectively measured by one observer, called Alice, while the other half is subjected to measurements performed sequentially, independently, and unsharply, by multiple observers, called B...
[Phys. Rev. A 98, 062304] Published Mon Dec 03, 2018

Author(s): Shane Mansfield and Elham Kashefi
We introduce a notion of contextuality for transformations in sequential contexts, distinct from the Bell-Kochen-Specker and Spekkens notions of contextuality. Within a transformation-based model for quantum computation we show that strong sequential-transformation contextuality is necessary and suf...
[Phys. Rev. Lett. 121, 230401] Published Mon Dec 03, 2018

Author(s): Martin Šiler, Luca Ornigotti, Oto Brzobohatý, Petr Jákl, Artem Ryabov, Viktor Holubec, Pavel Zemánek, and Radim Filip
Stochastic motion of particles in a highly unstable potential generates a number of diverging trajectories leading to undefined statistical moments of the particle position. This makes experiments challenging and breaks down a standard statistical analysis of unstable mechanical processes and their ...
[Phys. Rev. Lett. 121, 230601] Published Mon Dec 03, 2018

Author(s): Ranjith Nair
The problem of estimating multiple loss parameters of an optical system using the most general ancilla-assisted parallel strategy is solved under energy constraints. An upper bound on the quantum Fisher information matrix is derived assuming that the environment modes involved in the loss interactio...
[Phys. Rev. Lett. 121, 230801] Published Mon Dec 03, 2018

Author(s): Luca Dellantonio, Anders S. Sørensen, and Davide Bacco
Quantum key distribution (QKD) provides ultimate cryptographic security based on the laws of quantum mechanics. For point-to-point QKD protocols, the security of the generated key is compromised by detector side channel attacks. This problem can be solved with measurement-device-independent QKD (mdi...
[Phys. Rev. A 98, 062301] Published Mon Dec 03, 2018

Author(s): A. Bolt, D. Poulin, and T. M. Stace
Foliated quantum codes are a resource for fault-tolerant measurement-based quantum error correction for quantum repeaters and for quantum computation. They represent a general approach to integrating a range of possible quantum error correcting codes into larger fault-tolerant networks. Here, we pre...
[Phys. Rev. A 98, 062302] Published Mon Dec 03, 2018

Author(s): Ignacio Perito, Augusto J. Roncaglia, and Ariel Bendersky
The characterization of quantum processes is a key tool in quantum information processing tasks for several reasons: on one hand, it allows one to acknowledge errors in the implementations of quantum algorithms; on the other, it allows one to characterize unknown processes occurring in nature. Bende...
[Phys. Rev. A 98, 062303] Published Mon Dec 03, 2018