Rabi oscillations of a two-level atom appear as a quantum interference effect between the amplitudes associated with atomic superpositions, in analogy with the classic double-slit experiment which manifests a sinusoidal interference pattern. By extension, through direct detection of time-resolved resonance fluorescence from a quantum-dot neutral exciton driven in the Rabi regime, we experimentally demonstrate triple-slit-type quantum interference via quantum erasure in a V-type three-level artificial atom. This result is of fundamental interest in the experimental studies of the properties of V-type three-level systems and may pave the way for further insight into their coherence properties as well as applications for quantum information schemes. It also suggests quantum dots as candidates for multipath-interference experiments for probing foundational concepts in quantum physics.
Rabi oscillations of a two-level atom appear as a quantum interference effect between the amplitudes associated with atomic superpositions, in analogy with the classic double-slit experiment which manifests a sinusoidal interference pattern. By extension, through direct detection of time-resolved resonance fluorescence from a quantum-dot neutral exciton driven in the Rabi regime, we experimentally demonstrate triple-slit-type quantum interference via quantum erasure in a V-type three-level artificial atom. This result is of fundamental interest in the experimental studies of the properties of V-type three-level systems and may pave the way for further insight into their coherence properties as well as applications for quantum information schemes. It also suggests quantum dots as candidates for multipath-interference experiments for probing foundational concepts in quantum physics.
A commonly observed quantum-interference phenomenon is Rabi oscillations—understood as a ‘quantum beat’ between two dressed states separated by the Rabi splitting (RS) energy in a driven two-level (artificial) atom [1]. It is a signature of quantum coherence fundamental to the manipulation of atomic qubits in quantum information processing, and has been observed in quantum dots (QDs) (see Ref [2] and references therein). Another quantum-beat phenomenon occurs due to interference between the excited states of a V-type atomic system and has also been observed in the transient decay of QD emission from a suddenly excited neutral exciton state X0—an effective V-type system due to fine-structure splitting (FSS). Despite much related theoretical work and the availability of various platforms in which V-type systems could be realised, the observation of Rabi oscillations in resonance fluorescence from a coherently driven three-level V-type system remains a fundamentally interesting open question. In particular, quantum interference involving both RS and FSS has not been demonstrated experimentally. Here, through detection of time-resolved resonance fluorescence from a QD neutral exciton driven in the Rabi regime (Fig. 1), we experimentally demonstrate triple-slit-type quantum interference in a V-type three-level artificial atom [3]. This result is of fundamental interest in the experimental studies of the properties of V-type systems and may pave the way for further insight into their coherence properties. It also suggests QDs as candidates for multi-path-interference experiments for probing foundational concepts in quantum physics [4]. [1] Haroche, S. & Raimond, J.-M. Exploring the Quantum: Atoms, Cavities, and Photons. OUP Oxford, (2006). [2] Dada, A. C., et al. Optica 3, 493–498 (2016). [3] Dada, A. C., et al. arXiv preprint arXiv:1703.02308 (2017). [4] Sinha, U., Couteau, C., Jennewein, T., Laflamme, R., & Weihs, G. Science 329, 418–421 (2010).
The spectrum of quantum fluctuations in phase quadratures of resonance fluorescence of a three-level V-type atom driven by a coherent field is investigated. We find that quantum interference between two decay channels of the atom can greatly modify the spectrum. We show that for weak excitation, quantum interference can greatly enhance squeezing and change the phase quadrature in which the maximum squeezing occurs. We also show that for strong and far-off-resonance excitation two deeply squeezing peaks appear at the Rabi sideband frequencies and quantum interference broadens the squeezing peaks.
Based on a calculation model, we study the interference phenomena of serially coupled V-type and Λ-type triple quantum dots (CTQDs) driven simultaneously by a strong driving field and a weak probe field. Strongly depending on the configuration of the three-level CTQD, the probe absorption spectra, which are shown in the tunneling current, exhibit various quantum coherence properties. In the case where the two pairs of transitions of the CTQD have a small eigenfrequency difference Δω, the double-coupling effect of the driving field results in two Autler—Townes doublets and one weak Mollow triplet in one spectrum. With the value of Δω increasing, only one Autler—Townes splitting remains due to the single-coupling of the field. We also find that the effect of spontaneous emission of phonons may lead to an obvious background current, which can be used to distinguish which transition is driven by the driving field in experiment. The interesting quantum property of a CTQD revealed in our results suggests its potential applications in quantum modulators and quantum logic devices.
Summary form only given. We present direct experimental evidence of Rabi oscillation (RO) in individual self-assembled quantum dots (SAQDs) and experimental observation of a new quantum interference (QI) phenomenon. Our detailed theoretical investigations attribute this phenomenon to the coherent dynamics resulting from the interplay between RO and QI. We conduct experiments on an In/sub 0.5/Ga/sub 0.5/As SAQD, which can be considered as a three level system To study the interplay of RO and QI, we perform single dot wavepacket interferometry measurements in the strong excitation regime.
Young's double-slit interference experiment is central to quantum mechanics. While it has been demonstrated that an array of atoms can produce interference in light, it is a fundamental question to ask whether a single atom can act as a double slit when prepared in a superposition of two separate positions. Cohen-Tannoudji et al. [Proceedings of the Tenth International Conference on Laser Spectroscopy, edited by M. Ducloy, E. Giacobino, and G. Camy (World Scientific, Singapore, 1992), pp. 3--14] showed that the cross section of the light scattered by a single atom is independent of the spatial separation. In this work, however, we show that when a single atom tunneling in a double well is coupled to an optical ring cavity, the interference phenomena arise if the tunneling rate is comparable to the cavity linewidth. Being driven by an external laser in the dispersive regime, the field emitted by the atom into the cavity exhibits an interference pattern when varying the double-well spacing. Super-Poissonian bunched light can also be generated near the destructive interference. Furthermore, we show that the atomic flux of the coherent tunneling motion generates directional cavity emission, which oscillates for many cycles before the decoherence of the atomic motion and the decay of the cavity photons. Our work opens ways to manipulate photons with controllable external states of atoms for quantum information applications and use cavity light as nondestructive measurements for many-body states of atomic systems.
Transient nonlinear optical spectroscopy, performed on excitons confined to single GaAs quantum dots, shows oscillations that are analogous to Rabi oscillations in two-level atomic systems. This demonstration corresponds to a one-qubit rotation in a single quantum dot which is important for proposals using quantum dot excitons for quantum computing. The dipole moment inferred from the data is consistent with that directly obtained from linear absorption studies. The measurement extends the artificial atom model of quantum dot excitonic transitions into the strong-field limit, and makes possible full coherent optical control of the quantum state of single excitons using optical pi pulses.