We demonstrate that quantum information processing can be implemented with ions trapped in a far detuned optical cavity. For sufficiently large detuning the system becomes insensitive to cavity decay. Following recent experimental progress, this scheme can be implemented with currently available technology.
We show that a broadband Fabry-Perot microcavity can assist an emitter coupled to an off-resonant plasmonic nanoantenna to inhibit the nonradiative channels that affect the quenching of fluorescence. We identify the interference mechanism that creates the necessary enhanced couplings and bandwidth narrowing of the hybrid resonance and show that it can assist entering into the strong coupling regime. Our results provide new possibilities for improving the efficiency of solid-state emitters and accessing diverse realms of photophysics with hybrid structures that can be fabricated using existing …
We present a thorough analysis of single atom detection using optical cavities. The large set of parameters that influence the signal-to-noise ratio for cavity detection is considered, with an emphasis on detunings, probe power, cavity finesse and photon detection schemes. Real device operating restrictions for single photon counting modules and standard photodiodes are included in our discussion, with heterodyne detection emerging as the clearly favourable technique, particularly for detuned detection at high power.
The connectivity and tunability of superconducting quantum devices provide a rich platform to build quantum simulators and study novel many-body physics. Here we study quantum phase transition in a detuned multi-connected Jaynes-Cummings lattice, which can be constructed with superconducting circuits. This model is composed of alternatively connected qubits and cavity modes. Using a numerical method, we show that by varying the detuning between the qubits and the cavities, a phase transition from the superfluid phase to the Mott insulator phase occurs at commensurate fillings in a one-dimensio…
We study how to control the dynamics of tripartite entanglement among optical cavities using non-Markovian baths. In particular, we demonstrate how the reservoir engineering through the utilization of non-Markovian baths with different types of Lorentzian and ohmic spectral densities can lead to an entanglement survival for longer times and in some cases considerable regain of seemingly lost entanglement. Both of these behaviors indicate a better sustainability of entanglement (in time) compared to the usual Markovian bath situations which assumes a flat spectrum of the bath around the system …
A potential scheme is proposed to generate complete sets of entangled photons in the context of cavity quantum electrodynamics (QED). The scheme includes twice interactions of atoms with cavities, in which the first interaction is made in two-mode optical cavities and the second one exists in a microwave cavity. In the optical cavities the atoms are resonant with the cavity modes, while the detuned interaction of the atoms with a single-mode of the microwave cavity is driven by a classical field. We show that our scheme is carried out with higher efficiency than previeous schemes, and is close…
Multi-photon interference is at the heart of photonic quantum technologies. Arrays of integrated cavities can support bright sources of single-photons with high purity and small footprint, but the inevitable spectral distinguishability between photons generated from non-identical cavities is an obstacle to scaling. In principle, this problem can be alleviated by measuring photons with high timing resolution, which erases spectral information through the time-energy uncertainty relation. Here, we experimentally demonstrate that detection can be implemented with a temporal resolution sufficient …
The processing of information and computation is undergoing a paradigmatic shift since the realization of the enormous potential of quantum features to perform these tasks. Coupled cavity array is one of the well-studied systems to carry out these tasks. It is a versatile platform for quantum networks for distributed information processing and communication. Cavities have the salient feature of retaining photons for longer durations, thereby enabling them to travel coherently through the array without losing them in dissipation. Many quantum information protocols have been implemented in array…
The dynamics of a system composed of two coupled optical cavities, each containing a single two-level atom, is studied over a wide range of detuning and coupling values. A description of the field in terms of delocalized modes reveals that the detuning between the atoms and these modes is controlled by the coupling between the cavities; this detuning in turn governs the nature of the dynamics. If the atoms are highly detuned from both delocalized field modes, the dynamics becomes dispersive and an excitation may be transferred from the first atom to the second without populating the field. In …
Both cavity QED and photons are promising candidates for quantum information processing. We consider a combination of both candidates with a single photon going through spatially separate cavities to entangle the atomic qubits, based on the input-output process of the cavities. We present a general expression for the input-output process regarding the low-Q cavity confining a single atom, which works in a wide range of parameters. Focusing on low-Q cavity case, we propose some schemes for quantum information processing with Faraday rotation using single photons, which is much different from th…
A novel regime of atom-cavity physics is explored, arising when large atom samples dispersively interact with high-finesse optical cavities. A stable far detuned optical lattice of several million rubidium atoms is formed inside an optical ring resonator by coupling equal amounts of laser light to each propagation direction of a longitudinal cavity mode. An adjacent longitudinal mode, detunedby about 3 GHz, is used to perform probe transmission spectroscopy of the system. The atom-cavity coupling for the lattice beams and the probe is dispersive and dissipation results only from the finite pho…
By virtue of a silicon high-Q photonic crystal nanocavity, we propose and examine theoretically interactions between a stationary electron spin qubit of a semiconductor nanocrystal and a flying photon qubit. Firstly, we introduce, derive and demonstrate for the first time the explicit conditions towards realization of a spin-photon two-qubit phase gate, and propose these interactions as a generalized quantum interface for quantum information processing. Secondly, we examine novel single-spin-induced reflections as direct evidence of intrinsic bare and dressed modes in our coupled nanocrystal-c…
Propagation of light pulses through negative group velocity media is known to give rise to a number of paradoxical situations that seem to violate causality. The solution of these paradoxes has triggered the investigation of a number of interesting and unexpected features of light propagation. Here we report a combined theoretical and experimental study of the ring-down oscillations in optical cavities filled with a medium with such a strongly negative frequency dispersion to give a negative round-trip group delay time. We theoretically anticipate that causality imposes the existence of additi…
We develop a theory of parametric resonance in tunable superconducting cavities. The nonlinearity introduced by the SQUID attached to the cavity, and damping due to connection of the cavity to a transmission line are taken into consideration. We study in detail the nonlinear classical dynamics of the cavity field below and above the parametric threshold for the degenerate parametric resonance, featuring regimes of multistability and parametric radiation. We investigate the phase-sensitive amplification of external signals on resonance, as well as amplification of detuned signals, and relate th…
Josephson junctions have been shown to be a promising solid-state system for implementation of quantum computation. The significant two-qubit gates are generally realized by the capacitive coupling between the nearest neighbour qubits. We propose an effective Hamiltonian to describe charge qubits coupled through the cavity. We find that nontrivial two-qubit gates may be achieved by this coupling. The ability to interconvert localized charge qubits and flying qubits in the proposed scheme implies that quantum network can be constructed using this large scalable solid-state system.
The on-chip generation of non-classical states of light is a key-requirement for future optical quantum hardware. In solid-state cavity quantum electrodynamics, such non-classical light can be generated from self-assembled quantum dots strongly coupled to photonic crystal cavities. Their anharmonic strong light-matter interaction results in large optical nonlinearities at the single photon level, where the admission of a single photon into the cavity may enhance (photon-tunnelling) or diminish (photon-blockade) the probability for a second photon to enter the cavity. Here, we demonstrate that …
In this article we explore the dynamics of many-body atomic systems symmetrically coupled to a single Lorentzian photonic cavity. Our study reveals interesting dynamical characteristics including non-zero steady states, superradiant decay, enhanced energy transfer and the ability to modulate oscillations in the atomic system by tuning environmental degrees of freedom. We also analyse a configuration consisting of a three-atom chain embedded in a photonic cavity. Similarly, we find a strong enhancement of the energy transfer rate between the two ends of the chain and identified specific initial…
Entanglement distribution over quantum networks has the promise of realizing fundamentally new technologies. Entanglement between separated quantum processing nodes has been achieved on several experimental platforms in the past decade. To move towards metropolitan-scale quantum network test beds, the creation and transmission of indistinguishable single photons over existing telecom infrastructure is key. Here we report the interference of photons emitted by remote, spectrally detuned NV center-based network nodes, using quantum frequency conversion to the telecom L-band. We find a visibility…
We propose a scheme to generate two-photon, two-atom, or atom-photon entangledstates with a coupled system of two cavities. In our scheme, two cavity photonsare exchanged by the direct inter-cavity coupling, while atoms in the cavitiessimply play the role of generating and probing them. By virtue of the highefficiency of atomic state measurement, this method enables the realization ofefficient heralded entanglement generation robust against photon loss, whichgreatly facilitates applications in quantum information processing.
The ability to control spins in semiconductors is important in a variety of fields including spintronics and quantum information processing. Due to the potentially fast dephasing times of spins in the solid state [1-3], spin control operating on the picosecond or faster timescale may be necessary. Such speeds, which are not possible to attain with standard electron spin resonance (ESR) techniques based on microwave sources, can be attained with broadband optical pulses. One promising ultrafast technique utilizes single broadband pulses detuned from resonance in a three-level Lambda system [4].…
We propose an unconventional scheme for quantum entangled state distribution (QESD) and quantum state transfer~(QST) based on a fiber-cavity-atom system, in which three atoms are confined, respectively, in three bimodal cavities connected with each other by optical fibers. The key feature of the scheme is the virtual excitation of photons, which yields QESD and QST between the two atoms in the edge-cavities conditioned on one-step operation only on the atom in the middle cavity. No actual operation is performed on the two atoms in the edge cavities throughout the scheme. Robustness of the sche…
Two coupled-cavity systems, or "photonic dimers", are efficient test-beds for both fundamental optics -the realization of quantum correlated states, Josephson physics, and so forth-, and applications such as optical flip-flop memories. In this work we report on the first observation of nonlinear mode interaction in a photonic dimer formed by two semiconductor photonic crystal coupled nanolasers. For this, we investigate energy transfer between hybrid modes, which manifests as a switching from the blue-detuned (bonding) to the red-detuned (anti-bonding) modes. An mean-field model allows us to e…
We present the experimental observation of an optical spring without the use of an optical cavity. The optical spring is produced by interference at a beamsplitter and, in principle, does not have the damping force associated with optical springs created in detuned cavities. The experiment consists of a Michelson-Sagnac interferometer (with no recycling cavities) with a partially reflective GaAs microresonator as the beamsplitter that produces the optical spring. Our experimental measurements at input powers of up to 360 mW show the shift of the optical spring frequency as a function of power …
We show how an initially prepared quantum state of a radiation mode in a cavity can be preserved for a long time using a feedback scheme based on the injection of appropriately prepared atoms. We present a feedback scheme both for optical cavities, which can be continuously monitored by a photodetector, and for microwave cavities, which can be monitored only indirectly via the detection of atoms that have interacted with the cavity field. We also discuss the possibility of applying these methods for decoherence control in quantum information processing.
Using the highly detuned interaction between three-level $Λ$-type atoms and coherent optical fields, we can realize the C-NOT gates from atoms to atoms, optical fields to optical fields, atoms to optical fields and optical fields to atoms. Based on the realization of the C-NOT gates we propose an entanglement purification scheme to purify a mixed entangled states of coherent optical fields. The simplicity of the current scheme makes it possible that it will be implemented in experiment in the near future.
Cascaded optical cavities appear in various quantum information processing schemes in which atomic qubits are sitting in separate cavities interconnected by photons as flying qubits. The usual theoretical description relies on a coupled-mode Hamiltonian approach. Here we investigate the system of cascaded cavities without modal decomposition by using a scattering model approach and determine the validity regime of the coupled-mode models.
In this paper, correlation dynamics for two two-level atoms distributed in two isolated thermal cavities are studied, where the atomic state is initially prepared in a maximum entangled zero-and-two-excitation superposition state. We use two nonclasscal measures including geometric quantum discord via Schatten one norm and concurrence to analyze correlation dynamics for the two atoms when the two cavities have the same or different mean photon numbers. We find though correlation dynamics for these two measures have different features, they have the same characteristics in some particular time …
We present evidence of cavity quantum electrodynamics from a sparse density of strongly quantum-confined Pb-chalcogenide nanocrystals (between 1 and 10) approaching single-dot levels on moderately high-Q mesoscopic silicon optical cavities. Operating at important near-infrared (1500-nm) wavelengths, large enhancements are observed from devices and strong modifications of the QD emission are achieved. Saturation spectroscopy of coupled QDs is observed at 77K, highlighting the modified nanocrystal dynamics for quantum information processing.
Quantum state transfer between cavities is crucial for quantum information processing and quantum computation in optomechanical systems. Here, we present the first scheme for the transitionless intra-cavity quantum state transfer based on transitionless quantum driving (TQD) algorithm in optomechanical systems. We also present a physically feasible system for the TQD process based on largely detuned optomechanical cavity. With the Gaussian time-dependence coupling strengths, our scheme can achieve the perfect quantum state transfer with no undesired transition and reduce the dependence of accu…
We propose a scheme to prepare a maximally entangled state for two Lambda-type atoms trapped in separate optical cavities coupled through an optical fiber based on the combined effect of the unitary dynamics and the dissipative process. Our work shows that the fiber loss, as well as the atomic spontaneous emission and the cavity decay, is no longer undesirable, but requisite to prepare the distributed entanglement, which is meaningful for the long distance quantum information processing tasks. Originating from an arbitrary state, the desired state could be prepared without precise time control…
The response to a probe laser beam of a suspended, misaligned and detuned optical cavity is examined. A five degree of freedom model of the fluctuations of the longitudinal and transverse mirror coordinates is presented. Classical and quantum mechanical effects of radiation pressure are studied with the help of the optical stiffness coefficients and the signals provided by an FM sideband technique and a quadrant detector, for generic values of the product $\varpi τ$ of the fluctuation frequency times the cavity round trip. A simplified version is presented for the case of small misalignments. …
Based on a multimode multilevel Jaynes-Cummings model and multiphoton resonance theory, a set of universal two- and three-qubit gates, namely the iSWAP and the Fredkin gates, has been realized where dual-rail qubits are encoded in cavities. In this way the information has been stored in cavities and the off-resonant atomic levels have been eliminated by the semi-classical theory of an effective two-level Hamiltonian. A further semi-classical model, namely the spin-$J$ model, has been introduced so that a complete population inversion for levels of interest has been achieved and periodic multil…
We study transfer of single photon in an one-dimensional finite Glauber-Fock cavity array whose coupling strengths satisfy a square root law. The evolved state in the array can be mapped to an upper truncated coherent state if the cavities are resonant. Appropriate choices of resonance frequencies provide perfect transfer of a photon between any two cavities in the array. Perfect transfer of the photon allows perfect quantum state transfer between the cavities. Our findings may help in realizing quantum communication and information processing in photonic lattices.
Optical characterization of AlGaAs microdisk resonant cavities with a quantum dot active region is presented. Direct passive measurement of the optical loss within AlGaAs microdisk resonant structures embedded with InAs/InGaAs dots-in-a-well (DWELL) is performed using an optical-fiber-based probing technique at a wavelength (lambda~1400 nm) that is red-detuned from the dot emission wavelength (lambda~1200 nm). Measurements in the 1400 nm wavelength band on microdisks of diameter D = 4.5 microns show that these structures support modes with cold-cavity quality factors as high as 360,000. DWELL-…
We propose a novel scheme for high fidelity photonic controlled phase gates using Rydberg blockade in an ensemble of atoms in an optical cavity. The gate operation is obtained by first storing a photonic pulse in the ensemble and then scattering a second pulse from the cavity, resulting in a phase change depending on whether the first pulse contained a single photon. We show that the combination of Rydberg blockade and optical cavities effectively enhances the optical non-linearity created by the strong Rydberg interaction and thereby reduces the requirements for photonic quantum gates. The re…
Nonlinear Josephson circuits play a crucial role in the growing landscape of quantum information and technologies. The typical circuits studied in this field consist of qubits, whose anharmonicity is much larger than their linewidth, and also of parametric amplifiers, which are engineered with linewidths of tens of MHz or more. The regime of small anharmonicity but also narrow linewidth, corresponding to the dynamics of a high-$Q$ Duffing oscillator, has not been extensively explored using Josephson cavities. Here, we use two-tone spectroscopy to study the susceptibility of a strongly driven h…
Fast, efficient, and low power modulation of light at microwave frequencies is crucial for chip-scale classical and quantum processing as well as for long-range networks of superconducting quantum processors. A successful approach to bridge the gap between microwave and optical photons has been to use intermediate platforms such as acoustic waves, which can couple efficiently to a variety of quantum systems. Here, we use gigahertz-frequency focusing surface acoustic wave cavities on GaAs that are piezo-electrically coupled to superconducting circuits and parametrically coupled, via strain, to …
The transfer of quantum entanglement (or quantum coherence) is not only fundamental in quantum mechanics but also important in quantum information processing. We here propose a way to achieve the coherent transfer of $W$-class entangled states of qubits among different cavities. Because no photon is excited in each cavity, decoherence caused by the photon decay is suppressed during the transfer. In addition, only one coupler qubit and one operational step are needed and no classical pulses are used in this proposal, thus the engineering complexity is much reduced and the operation is greatly s…
Moving cavities promise to be a suitable system for relativistic quantum information processing. It has been shown that an inertial and a uniformly accelerated one-dimensional cavity can become entangled by letting an atom emit an excitation while it passes through the cavities, but the acceleration degrades the ability to generate entanglement. We show that in the two-dimensional case the entanglement generated is affected not only by the cavity's acceleration but also by its transverse dimension which plays the role of an effective mass.
In this paper, we study the fast and noise-resistant population transfer, quantum entangled states preparation, and quantum entangled states' transition by constructing the shortcuts to adiabatic passage (STAP) for multiparticle based on the approach of "Lewis-Riesenfeld invariants" in distant cavity quantum electronic dynamics (QED) system. Numerical simulation demonstrates that all of the schemes are fast and robust against the decoherence caused by atomic spontaneous emission and photon leakage. Moreover, not only the total operation time but also the robustness in each scheme against decoh…
Dynamic coupling of cavities to a quantum network is of major interest to distributed quantum information processing schemes based on cavity quantum electrodynamics. This can be achieved by active tuning a mediating atom-cavity system. In particular, we consider the dynamic coupling between two coupled cavities, each interacting with a two-level atom, realized by tuning one of the atoms. One atom-field system can be controlled to become maximally and minimally coupled with its counterpart, allowing high fidelity excitation confinement, Q-switching and reversible state transport. As an applicat…
The development of solid-state photonic quantum technologies is of great interest for fundamental studies of light-matter interactions and quantum information science. Diamond has turned out to be an attractive material for integrated quantum information processing due to the extraordinary properties of its colour centres enabling e.g. bright single photon emission and spin quantum bits. To control emitted photons and to interconnect distant quantum bits, micro-cavities directly fabricated in the diamond material are desired. However, the production of photonic devices in high-quality diamond …
We describe a system for long-distance distribution of quantum entanglement, in which coherent light with large average photon number interacts dispersively with single, far-detuned atoms or semiconductor impurities in optical cavities. Entanglement is heralded by homodyne detection using a second bright light pulse for phase reference. The use of bright pulses leads to a high success probability for the generation of entanglement, at the cost of a lower initial fidelity. This fidelity may be boosted by entanglement purification techniques, implemented with the same physical resources. The nee…
Three-dimensional (3D) superconducting microwave cavities with large mode volumes typically have high quality factors ($>10^6$). This is due to a reduced sensitivity to surface dielectric losses, which is the limiting source of dissipation in two-dimensional transmission line resonators. In recent years, 3D microwave cavities have been extensively used for coupling and interacting with superconducting quantum bits (qubits), providing a versatile platform for quantum information processing and hybrid quantum systems. A current issue that has arisen is that 3D superconducting cavities do not per…
We propose a method to implement cavity QED and quantum information processing in high-Q cavities with a single trapped but non-localized atom. The system is beyond the Lamb-Dick limit due to the atomic thermal motion. Our method is based on adiabatic passages, which make the relevant dynamics insensitive to the randomness of the atom position with an appropriate interaction configuration. The validity of this method is demonstrated from both approximate analytical calculations and exact numerical simulations. We also discuss various applications of this method based on the current experimenta…
Cavity-based large-scale quantum information processing (QIP) needs a large number of qubits and placing all of them in a single cavity quickly runs into many fundamental and practical problems such as the increase of cavity decay rate and decrease of qubit-cavity coupling strength. Therefore, future QIP most likely will require quantum networks consisting of a large number of cavities, each hosting and coupled to multiple qubits. In this work, we propose a way to prepare a $W$-class entangled state of spatially-separated multiple qubits in different cavities, which are connected to a coupler …
Excitons bound to flourine atoms in ZnSe have the potential for several quantum optical applications. Examples include optically accessible quantum memories for quantum information processing and lasing without inversion. These applications require the bound-exciton transitions to be coupled to cavities with high cooperativity factors, which results in the experimental observation of low-threshold lasing. We report such lasing from fluorine-doped ZnSe quantum wells in 3 and 6 micron microdisk cavities. Photoluminescence and selective photoluminescence spectroscopy confirm that the lasing is du…
Development of scalable quantum photonic technologies requires on-chip integration of components such as photonic crystal cavities and waveguides with nonclassical light sources. Recently, hexagonal boron nitride (hBN) has emerged as a promising platform for nanophotonics, following reports of hyperbolic phonon-polaritons and optically stable, ultra-bright quantum emitters. However, exploitation of hBN in scalable, on-chip nanophotonic circuits, quantum information processing and cavity quantum electrodynamics (QED) experiments requires robust techniques for the fabrication of monolithic optic…
Recirculating Quantum Photonic Networks for Fast Deterministic Quantum Information Processing
DTU Electro, Technical University of Denmark(丹麦技术大学电气工程系);NanoPhoton - Center for Nanophotonics, Technical University of Denmark(丹麦技术大学纳米光子学中心);Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology(麻省理工学院电气工程和计算机科学系)
Directional amplifiers are crucial nonreciprocal devices in both classical and quantum information processing. Here we propose a scheme for realizing a directional amplifier between optical and microwave fields based on an optomechanical system with optical gain, where an active optical cavity and two passive microwave cavities are, respectively, coupled to a common mechanical resonator via radiation pressure. The two passive cavities are coupled via hopping interaction to facilitate the directional amplification between the active and passive cavities. We obtain the condition of achieving opt…
We consider a network whose nodes are electromagnetic cavities, each coupled to a single three-level atom. The nodes are connected by optical fibers. Each atom is addressed by a control laser, which along with the cavity field drives atomic transitions. The network can be in the form of chain or two and three dimensional arrays of $N$-cavities connected by $N_B$ fibers. Following the work on two-cavity system by Pellizzari, we find that under certain conditions, the system possesses two kinds of dark states. The first kind are $N$ states corresponding to atomic excitations at each node and the…