University of Warsaw

High-dimensional quantum key distribution with resource-efficient detection

Maciej Ogrodnik, Adam Widomski, Dagmar Bruß +7

While quantum key distribution (QKD) based on two-dimensional (qubit) encoding is a mature, field-tested technology, its performance is lacking for many cryptographic applications.…

quant-ph2024★ 6 cited

Quantum Key Distribution with Basis-Dependent Detection Probability

Federico Grasselli, Giovanni Chesi, Nathan Walk +7

Quantum Key Distribution (QKD) is a promising technology for secure communication. Nevertheless, QKD is still treated with caution in certain contexts due to potential gaps between…

Pulsed Quantum Excitation

Juan Camilo López Carreño

A two-level system (2LS) is the most fundamental building block of matter. Its response to classical light is well known, as it converts pulses of coherent light into antibunched e…

quant-ph2024★ 2 cited

Tunable two-species spin models with Rydberg atoms in circular and elliptical states

Jacek Dobrzyniecki, Paula Heim, Michał Tomza

We propose a scheme for constructing versatile quantum simulators using ultracold Rydberg atoms in long-lived circular and elliptical states. By exciting different subspaces of int…

Lissajous dynamics of a quantum particle in a tilted two-dimensional discrete lattice

Grzegorz Jaczewski, Tomasz Sowiński

The quantum dynamics of a single particle in a discrete two-dimensional tilted lattice is analyzed from the perspective of the classical-quantum correspondence. Utilizing the fact…

quant-ph2024★ 3 cited

Many-body quantum resources of graph states

Marcin Płodzień, Maciej Lewenstein, Jan Chwedeńczuk

Characterizing the non-classical correlations of a complex many-body system is an important part of quantum technologies. A versatile tool for such a task is one that scales well w…

Universal bounds for quantum metrology in the presence of correlated noise

Stanislaw Kurdzialek, Francesco Albarelli, Rafal Demkowicz-Dobrzanski

We derive fundamental bounds for general quantum metrological models involving both temporal or spatial correlations (mathematically described by quantum combs), which may be effec…

quant-ph2024★ 1 cited

Violation of no-signaling on a public quantum computer

Tomasz Rybotycki, Tomasz Białecki, Josep Batle +1

No-signaling is a consequence of the no-communication theorem that states that bipartite systems cannot transfer information unless a communication channel exists. It is also a by-…

quant-ph2024★ 2 cited

Stories in the two-state vector formalism

Patryk Michalski, Andrzej Dragan

The two-state vector formalism of quantum mechanics is a time-symmetrized approach to standard quantum theory. In our work, we aim to establish rigorous foundations for the future…

quant-ph2024★ 1 cited

Efficient inference of quantum system parameters by Approximate Bayesian Computation

Lewis A. Clark, Jan Kolodynski

The ability to efficiently infer system parameters is essential in any signal-processing task that requires fast operation. Dealing with quantum systems, a serious challenge arises…

Characterizing out-of-distribution generalization of neural networks: application to the disordered Su-Schrieffer-Heeger model

Kacper Cybiński, Marcin Płodzień, Michał Tomza +3

Machine learning (ML) is a promising tool for the detection of phases of matter. However, ML models are also known for their black-box construction, which hinders understanding of…

CHSH Bell Tests For Optical Hybrid Entanglement

Morteza Moradi, Juan Camilo López Carreño, Adam Buraczewski +4

Optical hybrid entanglement can be created between two qubits, one encoded in a single photon and another one in coherent states with opposite phases. It opens the path to a variet…

quant-ph2024★ 7 cited

Entanglement classification and \emph{non-k}-separability certification via Greenberger-Horne-Zeilinger-class fidelity

Marcin Płodzień, Jan Chwedeńczuk, Maciej Lewenstein +1

Many-body quantum systems can be characterised using the notions of \emph{k}-separability and entanglement depth. A quantum state is \emph{k}-separable if it can be expressed as a…

Correlations and signaling in the Schrödinger-Newton model

Jacek Aleksander Gruca, Ankit Kumar, Ray Ganardi +3

The Schrödinger--Newton model is a semi-classical theory in which, in addition to mutual attraction, massive quantum particles interact with their own gravitational fields. While t…

Device-independent dimension leakage null test on qubits at low operational cost

Tomasz Rybotycki, Tomasz Białecki, Josep Batle +1

We construct a null test of the two-level space of a qubit, which is both device independent and needs a small number of different experiments. We demonstrate its feasibility on IB…

Inherent quantum resources in stationary spin chains

Marcin Płodzień, Jan Chwedeńczuk, Maciej Lewenstein

The standard way to generate many-body quantum correlations is via a dynamical protocol: an initial product state is transformed by interactions that generate non-classical correla…

quant-ph2024★ 7 cited

Second Law of Entanglement Manipulation with Entanglement Battery

Ray Ganardi, Tulja Varun Kondra, Nelly H. Y. Ng +1

A central question since the beginning of quantum information science is how two distant parties can convert one entangled state into another. It has been conjectured that such con…

quant-ph2024★ 6 cited

Efficient discrimination between real and complex quantum theories

Josep Batle, Tomasz Białecki, Tomasz Rybotycki +2

We improve the test to show the impossibility of a quantum theory based on real numbers by a larger ratio of complex-to-real bound on a Bell-type parameter. In contrast to previous…

Cross-platform certification of the qubit space with a minimal number of parameters

Tomasz Rybotycki, Tomasz Białecki, Josep Batle +2

We demonstrate a determinant dimension witness of a qubit space. Our test has a minimal number of independent parameters. We achieve it by mapping the Bloch sphere $π /2$ -rotation a…

Universal time scalings of sensitivity in Markovian quantum metrology

Arpan Das, Wojciech Gorecki, Rafal Demkowicz-Dobrzanski

Assuming Markovian time evolution of a quantum sensing system, we study the general characterization of the optimal sensitivity scalings with time, under most general quantum contr…

Quantum-enhanced joint estimation of phase and phase diffusion

Jayanth Jayakumar, Monika E. Mycroft, Marco Barbieri +1

Accurate phase estimation in the presence of unknown phase diffusive noise is a crucial yet challenging task in noisy quantum metrology. This problem is particularly interesting du…

quant-ph2024★ 10 cited

Noisy atomic magnetometry with Kalman filtering and measurement-based feedback

Julia Amoros-Binefa, Jan Kolodynski

Sensing a magnetic field with an atomic magnetometer operated in real time presents significant challenges, primarily due to sensor non-linearity, the presence of noise, and the ne…

quant-ph2024★ 14 cited

Quantum metrology using quantum combs and tensor network formalism

Stanislaw Kurdzialek, Piotr Dulian, Joanna Majsak +2

We develop an efficient algorithm for determining optimal adaptive quantum estimation protocols with arbitrary quantum control operations between subsequent uses of a probed channe…