Browse Physics

Photons stored in spatially separated superconducting resonators have now been entangled in a way that might be scalable to larger quantum networks.

Strain can be used to shift the resonant frequency of electron spin to the point where quantum processing starts looking feasible.

Networks of photonic devices with broken time-reversal symmetry may provide a way to create a quantum simulator to study strongly correlated systems.

Ensembles of dilute spin impurities in condensed matter systems can be accessed using microelectronic circuits and therefore may offer a way for long-term storage and enhanced processing of quantum information.

Vibrations of the atoms in a molecule are used to implement a Fourier transform orders of magnitude faster than possible with devices based on conventional electronics.

A trick for modulating optical frequency combs will enable more flexible control over trapped-ion qubits.

The signal-to-noise ratio for room-temperature readout of individual qubits can be substantially improved by taking an indirect route through intermediate energy levels.

Complex systems of entangled quantum states can now be transformed into a simpler form.

An entangled state of six photons could potentially carry quantum information over large distances and between different reference frames.

A theoretical analysis of recent experiments suggests that a key feature of a topological quantum computer—the unusual statistics of quasiparticles in the quantum Hall effect—may finally have been observed.

This design of atomic quantum memory tells us when a pulse of light has been successfully stored and then proceeds to retrieve it without significantly affecting its polarization. The exquisite operation provides a new capability for quantum information networks.

A proposal for obtaining optical resolution better than the classical limit by means of spatially entangled quantum states of light opens a new frontier in the fields of quantum optical imaging, metrology, and sensing.

Loading cold atoms into a hollow-core optical fiber enables all-optical switching with just several hundred photons.

A new algorithm allows for the extremely efficient calculation of thermally averaged quantities in one dimension, in conjunction with the density matrix renormalization group method. The key is the judicious selection of a few representative states.

Entanglement may not be the source of a quantum computer’s power. But if not, what is?

Two theoretical studies reveal how one might achieve electric-field control of spin in semiconductors, both in an impurity-localized electron, and also with a quantum dot molecule.

Preparing a harmonic oscillator in a state with a well-defined energy is a tricky business. With the new tools provided by cavity and circuit quantum electrodynamics it is now possible to make these pure quantum states and watch how they evolve in time.

Quantum measurements are conventionally thought of as irretrievably “collapsing” a wave function to the observed state. However, experiments with superconducting qubits show that the partial collapse resulting from a weak continuous measurement can be restored.

Laser beams made up of millions of sharply defined and coherently locked optical frequencies, called optical frequency combs, may provide a way to implement a powerful quantum computer.