In many states of the quantum electromagnetic field, including vacuum state, entanglement exists between different space-time regions---even spacelike separated ones. These correlations can be harvested and, thereby, detected by systems which locally interact with field. Here, we propose an experimental implementation such entanglement-harvesting scheme is based on electro-optic sampling (EOS). We demonstrate that state-of-the-art EOS experiments enable one to harvest from field and study...

Hail is a main contributor to weather-related damages buildings, cars, and agriculture in Switzerland, demanding actionable information on hail risks forecasts across sectors. The research project scClim addresses this demand by establishing seamless model chain from observing, modelling forecasting events the quantification of impacts, including simulations compare occurrence current future climate.Within project, we study several types impact-based warnings for addressing interests...

The state of a quantum system, adiabatically driven in cycle, may acquire measurable phase depending only on the closed trajectory parameter space. Such geometric phases are ubiquitous, and also underline physics robust topological phenomena such as Hall effect. Equivalently, be induced through cyclic sequence measurements. We show that application weak measurements renders trajectories, hence phase, stochastic. study concomitant probability distribution that, when varying measurement...

The generation and verification of genuine multipartite nonlocality (GMN) is central interest for both fundamental research quantum technological applications, such as privacy. To demonstrate GMN in measurement data, the statistics are commonly postselected by neglecting undesired data. Until now, valid postselection strategies have been restricted to local postselection. A general that decided after communication between parties can mimic nonlocality, even though complete data local. Here,...

Bounding the optimal precision in parameter estimation tasks is of central importance for technological applications. In regime a small number measurements, or low signal-to-noise ratios, meaning common frequentist bounds, such as Cramér-Rao bound (CRB), becomes questionable. Here, we discuss different (Barankin-like) approach to derive conditions existence estimators and calculate their variance, any measurement repetitions. We elaborate on connections shot-noise limit Kitaev phase...

Abstract Despite intensive research, the physical origin of speed-up offered by quantum algorithms remains mysterious. No general quantity, like, for instance, entanglement, can be singled out as essential useful resource. Here we report a close connection between trace speed and in Grover’s search algorithm implemented with pure pseudo-pure states. For noiseless algorithm, find one-to-one correspondence polarization state, which connected to wide class statistical speeds. time-dependent...

Machine-learning and neural-network approaches have gained huge attention in the context of quantum science technology recent years. One most essential tasks for future development technologies is verification nonclassical resources. Here, we present an artificial neural network approach identification states light based on recorded measurement statistics. In particular, implement train a which capable recognizing click statistics with multiplexed detectors. We use simulated data training...

The fast and accessible verification of nonclassical resources is an indispensable step towards a broad utilization continuous-variable quantum technologies. Here, we use machine learning methods for the identification nonclassicality states light by processing experimental data obtained via homodyne detection. For this purpose, train artificial neural network to classify classical from their quadrature-measurement distributions. We demonstrate that able correctly identify features real...

Quantum phase estimation (QPE) is the key subroutine of several quantum computing algorithms as well a central ingredient in computational chemistry and simulation. While QPE strategies have focused on single phase, applications to simultaneous phases may bring substantial advantages; for instance, presence spatial or temporal constraints. In this work, we study Bayesian algorithm parallel (simultaneous) multiple arbitrary phases. The protocol gives access correlations multi-phase...

Discarding undesirable measurement results in Bell experiments opens the detection loophole that prevents a conclusive demonstration of nonlocality. As closing represents major technical challenge for many practical experiments, it is customary to assume so-called fair sampling assumption (FSA) that, its original form, states collectively postselected statistics are sample ideal statistics. Here, we analyze FSA from viewpoint causal inference: We derive structure must be present any model...

In a crucial step for securing many existing quantum technologies, the authors use causal diagrams to close detection loophole in multipartite nonlocality demonstrations. Their results also imply that genuine $N$-partite can be created from $N$ independent photon sources.

Bounding the optimal precision in parameter estimation tasks is of central importance for technological applications. In regime a small number measurements, or that low signal-to-noise ratios, meaning common frequentist bounds such as Cram\'er-Rao bound (CRB) become questionable. Here, we discuss different linear (Barankin-like) conditions can be imposed on estimators and analyze when these admit an estimator with finite variance, any measurement repetitions. We show that, if larger than...

The future development of quantum technologies relies on creating and manipulating systems increasing complexity, with key applications in computation, simulation sensing. This poses severe challenges the efficient control, calibration validation states their dynamics. Although full large-scale may only be possible a computer, classical characterization optimization methods still play an important role. Here, we review different approaches that use post-processing techniques, possibly...

The geometric (Berry-Pancharatnam) phase originates from the intrinsic geometry of space quantum states and can be observed in different situations, such as a cyclic evolution system. Here, we utilize to obtain surprising insight: It is possible create nonlocal correlations fixed interferometer with independent photon inputs by varying photons' internal states.In particular, consider that fixed, i.e., has no variable shifts or subsequent measurement settings. Instead, choices parties...

The geometric (Berry-Pancharatnam) phase originates from the intrinsic geometry of space quantum states and can be observed in different situations, such as a cyclic evolution system. Here, we utilize to obtain surprising insight: It is possible create nonlocal correlations fixed interferometer with independent photon inputs by varying photons' internal states. In particular, consider that fixed, i.e., has no variable shifts or subsequent measurement settings. Instead, choices parties...

In many states of the quantum electromagnetic field, including vacuum state, entanglement exists between different space-time regions -- even space-like separated ones. These correlations can be harvested and, thereby, detected by systems which locally interact with field. Here, we propose an experimental implementation such entanglement-harvesting scheme is based on electro-optic sampling (EOS). We demonstrate that state-of-the-art EOS experiments enable one to harvest from field and study...

Discarding undesirable measurement results in Bell experiments opens the detection loophole that prevents a conclusive demonstration of nonlocality. As closing represents major technical challenge for many practical experiments, it is customary to assume so-called fair sampling assumption (FSA) that, its original form, states collectively postselected statistics are sample ideal statistics. Here, we analyze FSA from viewpoint causal inference: We derive structure must be present any model...

Genuine multipartite nonlocality (GMN), the strongest form of that describes fully collective nonlocal correlations among all experimental parties, can be observed when different distant parties each locally measure a particle from shared entangled many-particle state. For demonstration GMN, experimentally statistics are typically postselected: Events for which some do not detect must discarded. This coincidence postselection generally leads to detection loophole invalidates proper...

We predict a repulsive Casimir-Polder-type dispersion interaction between single neutron and metal or dielectric surface. consider scenario where is subject to an external magnetic field. Due its intrinsic moment, the then forms magnetisable two-level system which can exchange virtual photons with nearby The resulting purely object (neutron) electric one (surface) found be repulsive, in contrast typical attractive objects. Its magnitude considerably smaller than standard atom--surface...