Unitary transformations are routinely modeled and implemented in the field of quantum optics. In contrast, nonunitary transformations, which can involve loss and gain, require a different approach. ...In this work, we present a universal method to deal with nonunitary networks. An input to the method is an arbitrary linear transformation matrix of optical modes that does not need to adhere to bosonic commutation relations. The method constructs a transformation that includes the network of interest and accounts for full quantum optical effects related to loss and gain. Furthermore, through a decomposition in terms of simple building blocks, it provides a step-by-step implementation recipe, in a manner similar to the decomposition by Reck et al. Experimental Realization of Any Discrete Unitary Operator, Phys. Rev. Lett. 73, 58 (1994) but applicable to nonunitary transformations. Applications of the method include the implementation of positive-operator-valued measures and the design of probabilistic optical quantum information protocols.
•Synergistic effects of polypropylene addition in biomass co-pyrolysis process was been confirmed by ANOVA analysis.•The polypropylene has the most significant effect on liquid and gaseous fraction ...properties.•Influence of the material type on the elementary composition in char, liquid and gaseous product obtained in co-pyrolysis process was been described.
The aim of our study described in this article was statistical evaluation of the influence of process conditions on the chemical and physical properties of products obtained from biomass and plastic waste co-pyrolysis. To estimate the effects of the process conditions on the chemical and physical properties of products, analysis of variance (ANOVA) was used. Furthermore, a mathematical equation that can be used to determine the degree of change in chemical and physical properties of the solid, liquid and gaseous products from co-pyrolysis depending on process conditions is presented in this article. In investigation were used alder wood (hardwood) and pine wood (softwood) with polypropylene addition which were carbonized in various thermal conditions. In the presented studied was described significant effect among char, liquid and gaseous fraction properties according to polymer addition. Analysis of variance (ANOVA) employed to exploratory analysis shows that the type of material has the most significant effect on the nitrogen concentration in the char, the nitrogen and sulphur concentration in the liquid fraction and the carbon mono- and dioxide, methane concentration in gaseous fraction.
A scheme is proposed to generate a maximally entangled state between two qubits by means of a dissipation-driven process. To this end, we entangle the quantum states of qubits that are mutually ...coupled by a plasmonic nanoantenna. Upon enforcing a weak spectral asymmetry in the properties of the qubits, the steady-state probability to obtain a maximally entangled, subradiant state approaches unity. This occurs despite the high losses associated with the plasmonic nanoantenna that are usually considered as being detrimental. The entanglement scheme is shown to be quite robust against variations in the transition frequencies of the quantum dots and deviations in their prescribed position with respect to the nanoantenna. Our work paves the way for applications in the field of quantum computation in highly integrated optical circuits.
An optical nanoantenna and adjacent atomic systems are strongly coupled when an excitation is repeatedly exchanged between these subsystems prior to its eventual dissipation into the environment. It ...remains challenging to reach the strong-coupling regime but it is equally rewarding. Once they are achieved, promising applications such as signal processing at the nanoscale and at the single-photon level would immediately become available. Here, we study such hybrid configuration from different perspectives. The configuration we consider consists of two identical atomic systems, described in a two-level approximation, which are strongly coupled to an optical nanoantenna. First, we investigate when this hybrid system requires a fully quantum description, and we provide a simple analytical criterion. Second, a design for a nanoantenna is presented that enables the strong-coupling regime. In addition to a vivid time evolution, the strong coupling is documented in experimentally accessible quantities, such as the extinction spectra. The latter are shown to be strongly modified if the hybrid system is weakly driven and operates in the quantum regime. We find that the extinction spectra depend sensitively on the number of atomic systems coupled to the nanoantenna.
We suggest a hybrid plasmonic device made of a bimodal metallic nanoantenna coupled to an incoherently pumped quantum emitter. This device emits light into the two modes entangled in the number of ...photons. The process is a prime example of losses changing from being a nuisance into something beneficial, since, although it is counterintuitive, the entanglement is enabled by strong incoherent processes, i.e., the dominant scattering and absorption rates of the nanoantenna. This renders the nanoantenna an active source of nonclassicality. Both the high emission rate and the degree of entanglement of the emitted light are insensitive with respect to imperfections in the nanoantenna length, rendering the scheme feasible for an implementation.
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