Topic
Quantum coupling
About: Quantum coupling is a research topic. Over the lifetime, 140 publications have been published within this topic receiving 4112 citations.
Papers published on a yearly basis
Papers
TL;DR: This optomechanical system establishes an efficient quantum interface between mechanical oscillators and optical photons, which can provide decoherence-free transport of quantum states through optical fibres and offers a route towards the use of mechanical oscillator states as quantum transducers or in microwave-to-optical quantum links.
Abstract: Demonstration of an optomechanical system that works as a quantum interface between light and micro-mechanical motion. The possibility of controlling the quantum states of micro- and nanomechanical oscillators has been of great interest in recent years. Although various mechanical resonators have been cooled to their quantum ground state, there are few reports of experiments in which this quantum regime is further explored and used, for example, to exchange quantum information. Previously, quantum coupling between mechanical degrees of freedom and microwave radiation has been shown. Now, Verhagen et al. demonstrate an optomechanical system, cooled by radiation pressure, that works as a quantum interface between a mechanical oscillator and optical photons, offering the advantage that standard optical fibres can be used to extract the quantum information. Optical laser fields have been widely used to achieve quantum control over the motional and internal degrees of freedom of atoms and ions1,2, molecules and atomic gases. A route to controlling the quantum states of macroscopic mechanical oscillators in a similar fashion is to exploit the parametric coupling between optical and mechanical degrees of freedom through radiation pressure in suitably engineered optical cavities3,4,5,6. If the optomechanical coupling is ‘quantum coherent’—that is, if the coherent coupling rate exceeds both the optical and the mechanical decoherence rate—quantum states are transferred from the optical field to the mechanical oscillator and vice versa. This transfer allows control of the mechanical oscillator state using the wide range of available quantum optical techniques. So far, however, quantum-coherent coupling of micromechanical oscillators has only been achieved using microwave fields at millikelvin temperatures7,8. Optical experiments have not attained this regime owing to the large mechanical decoherence rates9 and the difficulty of overcoming optical dissipation10. Here we achieve quantum-coherent coupling between optical photons and a micromechanical oscillator. Simultaneously, coupling to the cold photon bath cools the mechanical oscillator to an average occupancy of 1.7 ± 0.1 motional quanta. Excitation with weak classical light pulses reveals the exchange of energy between the optical light field and the micromechanical oscillator in the time domain at the level of less than one quantum on average. This optomechanical system establishes an efficient quantum interface between mechanical oscillators and optical photons, which can provide decoherence-free transport of quantum states through optical fibres. Our results offer a route towards the use of mechanical oscillators as quantum transducers or in microwave-to-optical quantum links11,12,13,14,15.
1,010 citations
TL;DR: It is demonstrated that down to the nanometer length scales investigated classical electrodynamics still holds, and a full quantum description of electrodynamic phenomena in such systems might be required only when smaller gaps of a few angstroms are considered.
Abstract: We push the fabrication limit of gold nanostructures to the exciting sub-nanometer regime, in which light–matter interactions have been anticipated to be strongly affected by the quantum nature of electrons in metals. Doing so allows us to (1) evaluate the validity of classical electrodynamics to describe plasmonic effects at this length scale and (2) witness the gradual (instead of sudden) evolution of plasmon modes when two gold nanoprisms are brought into contact. Using electron energy-loss spectroscopy and transmission electron microscope imaging, we investigated nanoprisms separated by gaps of only 0.5 nm and connected by conductive bridges as narrow as 3 nm. Good agreement of our experimental results with electromagnetic calculations and LC circuit models evidence the gradual evolution of the plasmonic resonances toward the quantum coupling regime. We demonstrate that down to the nanometer length scales investigated classical electrodynamics still holds, and a full quantum description of electrodyna...
460 citations
TL;DR: The observed anticrossing occurs between excitons with predominant spatially direct and indirect character and reveals a field driven transition of the nature of the molecular ground state exciton wave function.
Abstract: We report the direct observation of quantum coupling in individual quantum dot molecules and its manipulation using static electric fields. A pronounced anticrossing of different excitonic transitions is observed as the electric field is tuned. A comparison of our experimental results with theory shows that the observed anticrossing occurs between excitons with predominant spatially direct and indirect character and reveals a field driven transition of the nature of the molecular ground state exciton wave function. Finally, the interdot quantum coupling strength is deduced optically and its dependence on the interdot separation is calculated.
412 citations
TL;DR: It is demonstrated that coherent quantum coupling between remote qubits can be achieved via certain classes of random, unpolarized (infinite temperature) spin chains through a new approach to quantum state transfer between remote spin qubits.
Abstract: We propose and analyze a new approach for quantum state transfer between remote spin qubits. Specifically, we demonstrate that coherent quantum coupling between remote qubits can be achieved via certain classes of random, unpolarized (infinite temperature) spin chains. Our method is robust to coupling-strength disorder and does not require manipulation or control over individual spins. In principle, it can be used to attain perfect state transfer over an arbitrarily long range via purely Hamiltonian evolution and may be particularly applicable in a solid-state quantum information processor. As an example, we demonstrate that it can be used to attain strong coherent coupling between nitrogen-vacancy centers separated by micrometer distances at room temperature. Realistic imperfections and decoherence effects are analyzed.
276 citations
TL;DR: In this paper, a bouquet of continuity bounds for quantum entropies is presented, falling broadly into two classes: first, a tight analysis of the Alicki-Fannes continuity bound for the conditional von Neumann entropy, reaching almost the best possible form that depends only on the system dimension and the trace distance of the states.
Abstract: We present a bouquet of continuity bounds for quantum entropies, falling broadly into two classes: first, a tight analysis of the Alicki–Fannes continuity bounds for the conditional von Neumann entropy, reaching almost the best possible form that depends only on the system dimension and the trace distance of the states. Almost the same proof can be used to derive similar continuity bounds for the relative entropy distance from a convex set of states or positive operators. As applications, we give new proofs, with tighter bounds, of the asymptotic continuity of the relative entropy of entanglement, E
R
, and its regularization $${E_R^{\infty}}$$
, as well as of the entanglement of formation, E
F
. Using a novel “quantum coupling” of density operators, which may be of independent interest, we extend the latter to an asymptotic continuity bound for the regularized entanglement of formation, aka entanglement cost, $${E_C=E_F^{\infty}}$$
. Second, we derive analogous continuity bounds for the von Neumann entropy and conditional entropy in infinite dimensional systems under an energy constraint, most importantly systems of multiple quantum harmonic oscillators. While without an energy bound the entropy is discontinuous, it is well-known to be continuous on states of bounded energy. However, a quantitative statement to that effect seems not to have been known. Here, under some regularity assumptions on the Hamiltonian, we find that, quite intuitively, the Gibbs entropy at the given energy roughly takes the role of the Hilbert space dimension in the finite-dimensional Fannes inequality.
234 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 13 |
| 2020 | 6 |
| 2019 | 12 |
| 2018 | 6 |
| 2017 | 6 |
| 2016 | 3 |