States, amplitudes, interference

We experimentally demonstrated a three-photon interference on a beam splitter between a weak coherent state and a two-photon state produced by a spontaneous parametric down conversion. It indicates that a combined three-photon probability amplitude, which is formed by the two-photon state and one-photon from the coherent state, can be used to interfere with another three-photon probability amplitude from the coherent state. The observed three-photon coincidence rate showed that the interference depended on not only the relative phase between the two interference field but also the amplitude of the weak coherent state. This may introduce another free parameter for preparing quantum state, such as high N00N state, with quantum interference.We experimentally demonstrated a three-photon interference on a beam splitter between a weak coherent state and a two-photon state produced by a spontaneous parametric down conversion. It indicates that a combined three-photon probability amplitude, which is formed by the two-photon state and one-photon from the coherent state, can be used to interfere with another three-photon probability amplitude from the coherent state. The observed three-photon coincidence rate showed that the interference depended on not only the relative phase between the two interference field but also the amplitude of the weak coherent state. This may introduce another free parameter for preparing quantum state, such as high N00N state, with quantum interference.

Optics ExpressJul 26, 20186 citations

Controlling quantum interference in phase space with amplitude

Yinghong Xue, Tingyu Li, Katsuyuki Kasai +3 more

We experimentally show a quantum interference in phase space by interrogating photon number probabilities (n = 2, 3, and 4) of a displaced squeezed state, which is generated by an optical parametric amplifier and whose displacement is controlled by amplitude of injected coherent light. It is found that the probabilities exhibit oscillations of interference effect depending upon the amplitude of the controlling light field. This phenomenon is attributed to quantum interference in phase space and indicates the capability of controlling quantum interference using amplitude. This remarkably contrasts with the oscillations of interference effects being usually controlled by relative phase in classical optics.We experimentally show a quantum interference in phase space by interrogating photon number probabilities (n = 2, 3, and 4) of a displaced squeezed state, which is generated by an optical parametric amplifier and whose displacement is controlled by amplitude of injected coherent light. It is found that the probabilities exhibit oscillations of interference effect depending upon the amplitude of the controlling light field. This phenomenon is attributed to quantum interference in phase space and indicates the capability of controlling quantum interference using amplitude. This remarkably contrasts with the oscillations of interference effects being usually controlled by relative phase in classical optics.

Scientific ReportsMay 17, 20175 citations

Interference effects

John Ewan Inglesfield

Physics EducationJul 1, 19770 citations

Interference and Measurements

Edward B. Manoukian

Springer eBooksJan 1, 20200 citations

Emergent Generator from Barrier Transport (Reduced Form)

Craig Edwin Holdway

T64 develops the projective-state geometry naturally induced by the interference and amplitude structures established in T61-T63. Once the reduced transport framework admits an exact complex amplitude-square representation, $P_{\mathrm{tot}}=|\psi|^2,$ global phase transformations of the form $\psi \sim e^{i\theta}\psi$ leave all amplitude-square observables invariant. The theorem therefore identifies physically equivalent amplitude states as phase-equivalence classes, producing a natural projective quotient structure on the reduced state space. Observable content depends only on the equivalence class of the amplitude representation rather than on a particular global phase representative. T64 is structurally important because it shifts the framework from interference algebra toward quotient-state geometry. The theorem shows that once interference-compatible complex amplitudes emerge, projective equivalence becomes unavoidable as a consequence of phase redundancy in the observable sector. The result does not derive the full structure of projective Hilbert-space quantum mechanics, but it establishes that the Q5 interference architecture naturally descends to a projective amplitude geometry after elimination of globally redundant phase information. Status: solid for the phase-equivalence and projective quotient structure induced by amplitude-square invariance; conditional on the amplitude representation framework established in T61-T63; speculative for any claim of complete equivalence with full quantum projective Hilbert geometry or wavefunction ontology.T64 develops the projective-state geometry naturally induced by the interference and amplitude structures established in T61-T63. Once the reduced transport framework admits an exact complex amplitude-square representation,\[P_{\mathrm{tot}}=|\psi|^2,\]global phase transformations of the form\[\psi \sim e^{i\theta}\psi\]leave all amplitude-square observables invariant. The theorem therefore identifies physically equivalent amplitude states as phase-equivalence classes, producing a natural projective quotient structure on the reduced state space. Observable content depends only on the equivalence class of the amplitude representation rather than on a particular global phase representative. T64 is structurally important because it shifts the framework from interference algebra toward quotient-state geometry. The theorem shows that once interference-compatible complex amplitudes emerge, projective equivalence becomes unavoidable as a consequence of phase redundancy in the observable sector. The result does not derive the full structure of projective Hilbert-space quantum mechanics, but it establishes that the Q5 interference architecture naturally descends to a projective amplitude geometry after elimination of globally redundant phase information. Status: solid for the phase-equivalence and projective quotient structure induced by amplitude-square invariance; conditional on the amplitude representation framework established in T61-T63; speculative for any claim of complete equivalence with full quantum projective Hilbert geometry or wavefunction ontology.

May 23, 20260 citations

P_{\mathrm{tot}}=|\psi|^2,

global phase transformations of the form

\psi \sim e^{i\theta}\psi

leave all amplitude-square observables invariant. The theorem therefore identifies physically equivalent amplitude states as phase-equivalence classes, producing a natural projective quotient structure on the reduced state space. Observable content depends only on the equivalence class of the amplitude representation rather than on a particular global phase representative. T64 is structurally important because it shifts the framework from interference algebra toward quotient-state geometry. The theorem shows that once interference-compatible complex amplitudes emerge, projective equivalence becomes unavoidable as a consequence of phase redundancy in the observable sector. The result does not derive the full structure of projective Hilbert-space quantum mechanics, but it establishes that the Q5 interference architecture naturally descends to a projective amplitude geometry after elimination of globally redundant phase information. Status: solid for the phase-equivalence and projective quotient structure induced by amplitude-square invariance; conditional on the amplitude representation framework established in T61-T63; speculative for any claim of complete equivalence with full quantum projective Hilbert geometry or wavefunction ontology.