152 citations · 959 across the 25 of their papers we have counts for
22 papers · 1 filter
Classical simulation of non-Gaussian bosonic circuits
Beatriz Dias, Robert Koenig
We propose efficient classical algorithms which (strongly) simulate the action of bosonic linear optics circuits applied to superpositions of Gaussian states. Our approach relies o…
How to fault-tolerantly realize any quantum circuit with local operations
Shin Ho Choe, Robert Koenig
We show how to realize a general quantum circuit involving gates between arbitrary pairs of qubits by means of geometrically local quantum operations and efficient classical comput…
Oscillator-to-oscillator codes do not have a threshold
Lisa Hänggli, Robert Koenig
It is known that continuous variable quantum information cannot be protected against naturally occurring noise using Gaussian states and operations only. Noh et al. (PRL 125:080503…
Correcting coherent errors with surface codes
Sergey Bravyi, Matthias Englbrecht, Robert Koenig +1
We study how well topological quantum codes can tolerate coherent noise caused by systematic unitary errors such as unwanted -rotations. Our main result is an efficient algorith…
Coherent state coding approaches the capacity of non-Gaussian bosonic channels
Stefan Huber, Robert Koenig
The additivity problem asks if the use of entanglement can boost the information-carrying capacity of a given channel beyond what is achievable by coding with simple product states…
On quantum additive Gaussian noise channels
Martin Idel, Robert Koenig
We give necessary and sufficient conditions for a Gaussian quantum channel to have a dilation involving a passive, i.e., number-preserving unitary. We then establish a normal form…
Geometric inequalities from phase space translations
Stefan Huber, Robert Koenig, Anna Vershynina
We establish a quantum version of the classical isoperimetric inequality relating the Fisher information and the entropy power of a quantum state. The key tool is a Fisher informat…
Preparing topologically ordered states by Hamiltonian interpolation
Xiaotong Ni, Fernando Pastawski, Beni Yoshida +1
We study the preparation of topologically ordered states by interpolating between an initial Hamiltonian with a unique product ground state and a Hamiltonian with a topologically d…
Matrix product approximations to multipoint functions in two-dimensional conformal field theory
Robert Koenig, Volkher B. Scholz
Matrix product states (MPS) illustrate the suitability of tensor networks for the description of interacting many-body systems: ground states of gapped -D systems are approximab…
Generating topological order: no speedup by dissipation
Robert Koenig, Fernando Pastawski
We consider the problem of preparing topologically ordered states using unitary and non-unitary circuits, as well as local time-dependent Hamiltonian and Liouvillian evolutions. We…
An optimal dissipative encoder for the toric code
John Dengis, Robert Koenig, Fernando Pastawski
We consider the problem of preparing specific encoded resource states for the toric code by local, time-independent interactions with a memoryless environment. We propose a constru…
Classification of topologically protected gates for local stabilizer codes
Sergey Bravyi, Robert Koenig
Given a quantum error correcting code, an important task is to find encoded operations that can be implemented efficiently and fault-tolerantly. In this Letter we focus on topologi…
Limits on classical communication from quantum entropy power inequalities
Robert Koenig, Graeme Smith
Almost all modern communication systems rely on electromagnetic fields as a means of information transmission, and finding the capacities of these systems is a problem of significa…
Classical simulation of dissipative fermionic linear optics
Sergey Bravyi, Robert Koenig
Fermionic linear optics is a limited form of quantum computation which is known to be efficiently simulable on a classical computer. We revisit and extend this result by enlarging…
Disorder-assisted error correction in Majorana chains
Sergey Bravyi, Robert Koenig
It was recently realized that quenched disorder may enhance the reliability of topological qubits by reducing the mobility of anyons at zero temperature. Here we compute storage ti…
Simplified instantaneous non-local quantum computation with applications to position-based cryptography
Salman Beigi, Robert Koenig
Instantaneous measurements of non-local observables between space-like separated regions can be performed without violating causality. This feat relies on the use of entanglement.…
Approximating Turaev-Viro 3-manifold invariants is universal for quantum computation
Gorjan Alagic, Stephen P. Jordan, Robert Koenig +1
The Turaev-Viro invariants are scalar topological invariants of compact, orientable 3-manifolds. We give a quantum algorithm for additively approximating Turaev-Viro invariants of…
Composite anyon coding and the initialization of a topological quantum computer
Robert Koenig
Schemes for topological quantum computation are usually based on the assumption that the system is initially prepared in a specific state. In practice, this state preparation is ex…
A strong converse for classical channel coding using entangled inputs
Robert Koenig, Stephanie Wehner
A fully general strong converse for channel coding states that when the rate of sending classical information exceeds the capacity of a quantum channel, the probability of correctl…
Simplifying quantum double Hamiltonians using perturbative gadgets
Robert Koenig
Perturbative gadgets were originally introduced to generate effective k-local interactions in the low-energy sector of a 2-local Hamiltonian. Extending this idea, we present gadget…
Locking of accessible information and implications for the security of quantum cryptography
Robert Koenig, Renato Renner, Andor Bariska +1
The unconditional security of a quantum key distribution protocol is often defined in terms of the accessible information, that is, the maximum mutual information between the distr…
On the Power of Quantum Memory
Robert Koenig, Ueli Maurer, Renato Renner
We address the question whether quantum memory is more powerful than classical memory. In particular, we consider a setting where information about a random n-bit string X is store…