اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدTuning the Fano Resonance with an Intruder Continuum
118
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Through a combination of experiment and theory we establish the possibility of achieving strong tuning of Fano resonances (FRs), by allowing their usual two-path geometry to interfere with an additional, intruder, continuum. As the coupling strength to this intruder is varied, we predict strong modulations of the resonance line shape that, in principle at least, may exceed the amplitude of the original FR itself. For a proof-of-concept demonstration of this phenomenon, we construct a nanoscale interferometer from nonlocally coupled quantum point contacts and utilize the unique features of their density of states to realize the intruder. External control of the intruder coupling is enabled by means of an applied magnetic field, in the presence of which we demonstrate the predicted distortions of the FR. This general scheme for resonant control should be broadly applicable to a variety of wave-based systems, opening up the possibility of new applications in areas such as chemical and biological sensing and secure communications.
قيم البحث
اقرأ أيضاً
We employ a recently developed quantization scheme for quasinormal modes (QNMs) to study a nonperturbative open cavity-QED system consisting of a hybrid metal-dielectric resonator coupled to a quantum emitter. This hybrid cavity system allows one to
explore the complex coupling between a low $Q$ (quality factor) resonance and a high $Q$ resonance, manifesting in a striking Fano resonance, an effect that is not captured by traditional quantization schemes using normal modes or a Jaynes-Cummings (JC) type model. The QNM quantization approach rigorously includes dissipative coupling between the QNMs, and is supplemented with generalized input-output relations for the output electric field operator for multiple modes in the system, and correlation functions outside the system. The role of the dissipation-induced mode coupling is explored in the strong coupling regime between the photons and emitter beyond the first rung of the JC dressed-state ladder. Important differences in the quantum master equation and input-output relations between the QNM quantum model and phenomenological dissipative JC models are found. In a second step, numerical results for the Fock distributions and system as well as output correlation functions obtained from the quantized QNM model for the hybrid structure are compared with results from a phenomenological approach. We demonstrate explicitly how the quantized QNM model manifests in multiphoton quantum correlations beyond what is predicted by the usual JC models.
We investigate the effect of decoherence on Fano resonances in wave transmission through resonant scattering structures. We show that the Fano asymmetry parameter q follows, as a function of the strength of decoherence, trajectories in the complex pl
ane that reveal detailed information on the underlying decoherence process. Dissipation and unitary dephasing give rise to manifestly different trajectories. Our predictions are successfully tested against microwave experiments using metal cavities with different absorption coefficients and against previously published data on transport through quantum dots. These results open up new possibilities for studying the effect of decoherence in a wide array of physical systems where Fano resonances are present.
Vacuum fluctuations of the electromagnetic field set a fundamental limit to the sensitivity of a variety of measurements, including magnetic resonance spectroscopy. We report the use of squeezed microwave fields, which are engineered quantum states o
f light for which fluctuations in one field quadrature are reduced below the vacuum level, to enhance the detection sensitivity of an ensemble of electronic spins at millikelvin temperatures.} By shining a squeezed vacuum state on the input port of a microwave resonator containing the spins, we obtain a $1.2$,dB noise reduction at the spectrometer output compared to the case of a vacuum input. This result constitutes a proof of principle of the application of quantum metrology to magnetic resonance spectroscopy.
We demonstrate a fully-tunable multi-state Fano system in which remotely-implemented quantum states interfere with each other through their coupling to a mutual continuum. On tuning these resonances near coincidence a robust avoided crossing is obser
ved, with a distinctive character that confirms the continuum as the source of the coupling. While the continuum often serves as a source of decoherence, our work therefore shows how its presence can instead also be essential to mediate the interaction of quantum states, a result that could allow new approaches to engineer the collective states of nanostructures.
A critical aspect of quantum mechanics is the nonlocal nature of the wavefunction, a characteristic that may yield unexpected coupling of nominally-isolated systems. The capacity to detect this coupling can be vital in many situations, especially tho
se in which its strength is weak. In this work we address this problem in the context of mesoscopic physics, by implementing an electron-wave realization of a Fano interferometer using pairs of coupled quantum point contacts (QPCs). Within this scheme, the discrete level required for a Fano resonance is provided by pinching off one of the QPCs, thereby inducing the formation of a quasi-bound state at the center of its self-consistent potential barrier. Using this system, we demonstrate a form of textit{nonequilibrium} Fano resonance (NEFR), in which nonlinear electrical biasing of the interferometer gives rise to pronounced distortions of its Fano resonance. Our experimental results are captured well by a quantitative theoretical model, which considers a system in which a standard two-path Fano interferometer is coupled to an additional, textit{intruder}, continuum. According to this theory, the observed distortions in the Fano resonance arise textit{only} in the presence of coupling to the intruder, indicating that the NEFR provides a sensitive means to infer the presence of weak coupling between mesoscopic systems.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
