Reversed interplay of quantum interference and which-way information in multiphoton entangled states

Abstract

We report experimental studies of the multi-photon quantum interference of a two-mode threephoton entangled Fock state |2, 1 + |1, 2 impinging on a two-port balanced beam splitter. When the distinguishability between the two input paths is increased, we observe a reduction followed by a resurgence of the quantum interference signal. We ascribe this unusual behavior to the competition among contributions from distinct numbers of interfering photons. Our theoretical analysis shows that this phenomenon will occur for any entangled Fock-state input of the form |N, M + |M, N where M, N > 0. Our results are an indication that wave-particle duality may give rise to a wide range of, largely unexplored, phenomena in multi-particle interference.PACS numbers: 03.65. Yz, 42.50.Ar, Quantum interference is one of the most fundamental features of quantum mechanics, observed in a variety of quantum systems [1][2][3][4][5]. A prototype example is the double slit experiment, where the repeated incidence of a single particle leaves wave-like interference fringes on a screen [1,6]. Perfect interference is only observed if no information is available about which path the particle has taken through the slits [7], while partial path distinguishability gradually reduces the fringe contrast [8,9]. For example, a time delay applied to one of the two paths yields which-path information and ultimately causes the interference fringes to vanish. Previous studies on interference of a single photon and two photons have thus shown that increasing the distinguishability simply reduces the interference fringe visibility [10][11][12][13][14], as a quantitative consequence of wave-particle duality [8,9].In this work, we study multi-photon interference and observe that, in contrast to the single-photon case, interference signals may vanish and reappear under a gradually increased path distinguishability. Our theoretical analysis reveals that the observed phenomena are not due to information erasure [15,16], non Markovian processes [17,18], or a periodic decoherence [19,20], but due to a passage between different numbers of interfering photons which exhibit distinct interference fringes. We find that with the exception of N 00N states, multi-photon states in general exhibit a nontrivial relationship between interference fringes and which-path distinguishability. Experimental results.- Figure 1(a) shows a schematic of our experimental setup to observe multi-photon interference. This setup, illuminated with the single-photon stateis equivalent to the aforementioned double-slit experiment [1,6], and single-photon detection at D d , denoted

Monotonic quantum-to-classical transition enabled by positively correlated biphotons

“…The photons in the model of Refs. [1,12,17] is spectrally uncorrelated, therefore, the experiment results in Ref [1,12] only correspond to Fig. 2(a2, a3, a4) in our simulation.…”

“…Our work have several applications in the future. Higher-order correlations in many-body system are very important for characterizing a quantum system and became to be a hot topic in study of quantum optics [17,33,34]. In this work, we studied the role of spectral correlation in a four-photon quantum interference, which actually corresponds to a fourth-order temporal correlation in a four-body system.…”

Disorder-Induced Dephasing in Backscattering-Free Quantum Transport

“…2(a)]. The latter are among the indispensable processing units in linear optics, quantum computation, quantum communication, and quantum foundations [3,5,[20][21][22][23]. Their optimal operation, based on constructive and destructive interference in the output arms (denoted as ±), respectively, assumes identical input states, where a phase shift ϕ in one input arm may determine the output probabilities, i.e., in the idealized case, prob ± (ϕ) = 1 2 (1 ± sin ϕ) (we assume balanced beam splitters).…”

Disorder-dressed quantum evolution

“…These variations may be caused, e.g., by impurities in the sample, stray fields, or limitations in their external control; for instance, accidental gate overrotations in quantum computing devices. In many cases, such disorder constitutes one of the dominant remaining sources of error [34][35][36][37][38][39][40][41][42][43][44][45].…”