Interferometric Mass Spectrometry.

Accelerator mass spectrometry (AMS) is a widely used technique with multiple applications, including geology, molecular biology, and archeology. In order to achieve a high dynamic range, AMS requires tandem accelerators and large magnets, which thus confines it to big laboratories. Here we propose interferometric mass spectrometry (Interf-MS), a novel method of mass separation which uses quantum interference.

Cyclic permutations for qudits in d dimensions.

One of the main challenges in quantum technologies is the ability to control individual quantum systems. This task becomes increasingly difficult as the dimension of the system grows. Here we propose a general setup for cyclic permutations X in d dimensions, a major primitive for constructing arbitrary qudit gates.

Publisher Correction: Is wave-particle objectivity compatible with determinism and locality?

This corrects the article DOI: 10.1038/ncomms5997.

Sorting quantum systems efficiently.

Measuring the state of a quantum system is a fundamental process in quantum mechanics and plays an essential role in quantum information and quantum technologies. One method to measure a quantum observable is to sort the system in different spatial modes according to the measured value, followed by single-particle detectors on each mode. Examples of quantum sorters are polarizing beam-splitters (PBS) - which direct photons according to their polarization - and Stern-Gerlach devices.

Determinism, independence, and objectivity are incompatible.

Hidden-variable models aim to reproduce the results of quantum theory and to satisfy our classical intuition. Their refutation is usually based on deriving predictions that are different from those of quantum mechanics. Here instead we study the mutual compatibility of apparently reasonable classical assumptions.

Is wave-particle objectivity compatible with determinism and locality?

Wave-particle duality, superposition and entanglement are among the most counterintuitive features of quantum theory. Their clash with our classical expectations motivated hidden-variable (HV) theories. With the emergence of quantum technologies, we can test experimentally the predictions of quantum theory versus HV theories and put strong restrictions on their key assumptions.

Proposal for a quantum delayed-choice experiment.

Gedanken experiments help to reconcile our classical intuition with quantum mechanics and nowadays are routinely performed in the laboratory. An important open question is the quantum behavior of the controlling devices in such experiments. We propose a framework to analyze quantum-controlled experiments and illustrate it by discussing a quantum version of Wheeler's delayed-choice experiment.