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Proposal for Quantum Optics Experiments Toward Experimental Verification of Temporal Bidirectionality: Verification Using High-Speed Beam Splitter Switching and Hong-Ou-Mandel Interference / 時間前後性の実験的検証に向けた量子光学実験の提案 - 高速ビームスプリッター切替とHong-Ou-Mandel干渉を用いた検証 -

Tsunehisa Chiba

Published Aug 28, 2026• 0 citations
Publisher

Abstract

[English] This paper formulates the hypothesis of "temporal bidirectionality" in quantum phenomena and proposes an experimental scheme for its verification using quantum optics. Here, temporal bidirectionality refers to the possibility that temporal degrees of freedom corresponding to both before and after a process contribute to quantum state formation and interference. Specifically, we propose an experimental setup using Mach-Zehnder and Hong-Ou-Mandel (HOM) interferometers with high-speed optical path switching at frequency f. By introducing a characteristic time scale Δt, we establish a framework to compare standard quantum mechanical predictions against temporal bidirectionality models based on the frequency dependence of interference visibility V(f) and HOM dip parameters. The primary objective of this study is not to assert the existence of temporal bidirectionality a priori, but to translate a novel hypothesis on the structure of time into a falsifiable quantum optical test. [日本語] 本論文では、量子現象における「時間前後性 (temporal bidirectionality)」という仮説を定式化し、量子光学を用いた実験的検証方法を提案する。時間前後性とは、量子状態の形成や干渉過程において、通常の因果的記述に加え、時間の前後に対応する自由度が現象に寄与する可能性を指す。 具体的には、二光路干渉計やHong-Ou-Mandel (HOM) 干渉計において、ビームスプリッター等の光路選択機構を高速(切替周波数 f)に切り替え、干渉可視度 V(f) やHOM dipの変化を測定する手法を示す。標準量子力学の予測(VSQM)と時間前後性モデルの予測(VFB)を比較し、特徴的時間スケール Δt に対応する周波数領域において生じ得る異常な周波数依存性を検証する枠組みを提示する。 本研究の目的は時間前後性の存在を事前に主張することではなく、時間の構造に関する新しい仮説を反証可能な物理モデルとして評価・検証することにある。

DOI
10.5281/zenodo.22140292

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Proposal for Quantum Optics Experiments Toward Experimental Verification of Temporal Bidirectionality: Verification Using High-Speed Beam Splitter Switching and Hong-Ou-Mandel Interference / 時間前後性の実験的検証に向けた量子光学実験の提案 - 高速ビームスプリッター切替とHong-Ou-Mandel干渉を用いた検証 -

恒久 千葉

説明 (Description): [English] This paper formulates the hypothesis of "temporal bidirectionality" in quantum phenomena and proposes an experimental scheme for its verification using quantum optics. Here, temporal bidirectionality refers to the possibility that temporal degrees of freedom corresponding to both before and after a process contribute to quantum state formation and interference. Specifically, we propose an experimental setup using Mach-Zehnder and Hong-Ou-Mandel (HOM) interferometers with high-speed optical path switching at frequency f. By introducing a characteristic time scale Δt, we establish a framework to compare standard quantum mechanical predictions against temporal bidirectionality models based on the frequency dependence of interference visibility V(f) and HOM dip parameters. The primary objective of this study is not to assert the existence of temporal bidirectionality a priori, but to translate a novel hypothesis on the structure of time into a falsifiable quantum optical test. [日本語] 本論文では、量子現象における「時間前後性 (temporal bidirectionality)」という仮説を定式化し、量子光学を用いた実験的検証方法を提案する。時間前後性とは、量子状態の形成や干渉過程において、通常の因果的記述に加え、時間の前後に対応する自由度が現象に寄与する可能性を指す。 具体的には、二光路干渉計やHong-Ou-Mandel (HOM) 干渉計において、ビームスプリッター等の光路選択機構を高速(切替周波数 f)に切り替え、干渉可視度 V(f) やHOM dipの変化を測定する手法を示す。標準量子力学の予測(VSQM)と時間前後性モデルの予測(VFB)を比較し、特徴的時間スケール Δt に対応する周波数領域において生じ得る異常な周波数依存性を検証する枠組みを提示する。 本研究の目的は時間前後性の存在を事前に主張することではなく、時間の構造に関する新しい仮説を反証可能な物理モデルとして評価・検証することにある。

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Quantum mechanics, optics and indeed any wave theory exhibits the phenomenon of interference. In this thesis we present two problems investigating interference due to indistinguishable alternatives and a mostly unrelated investigation into the free space propagation speed of light pulses in particular spatial modes. In chapter 1 we introduce the basic properties of the electromagnetic field needed for the subsequent chapters. In chapter 2 we review the properties of interference using the beam splitter and the Mach-Zehnder interferometer. In particular we review what happens when one of the paths of the interferometer is marked in some way so that the particle having traversed it contains information as to which path it went down (to be followed up in chapter 3) and we review Hong-Ou-Mandel interference at a beam splitter (to be followed up in chapter 5). In chapter 3 we present the first of the interference problems. This consists of a nested Mach-Zehnder interferometer in which each of the free space propagation segments are weakly marked by mirrors vibrating at different frequencies [1]. The original experiment drew the conclusions that the photons followed disconnected paths. We partition the description of the light in the interferometer according to the number of paths it contains which-way information about and reinterpret the results reported in [1] in terms of the interference of paths spatially connected from source to detector. In chapter 4 we briefly review optical angular momentum, entanglement and spontaneous parametric down conversion. These concepts feed into chapter 5 in which we present the second of the interference problems namely Hong-Ou-Mandel interference with particles possessing two degrees of freedom. We analyse the problem in terms of exchange symmetry for both boson and fermion pairs and show that the particle statistics at a beam splitter can be controlled for suitably chosen states. We propose an experimental test of these ideas using orbital angular momentum entangled photons. In chapter 6 we look at the effect that the transverse spatial structure of the mode that a pulse of light is excited in has on its group velocity. We show that the resulting group velocity is slower than the speed of light in vacuum for plane waves and that this reduction in the group velocity is related to the spread in the wave vectors required to create the transverse spatial structure. We present experimental results of the measurement of this slowing down using Hong-Ou-Mandel interference.

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時間前後性の実験的検証に向けた量子光学実験の提案 ― 高速ビームスプリッター切替とHong–Ou–Mandel干渉を用いた検証 ―

恒久 千葉

タイトル (Title): Proposal for Quantum Optics Experiments Toward Experimental Verification of Temporal Bidirectionality: Verification Using High-Speed Beam Splitter Switching and Hong-Ou-Mandel Interference / 時間前後性の実験的検証に向けた量子光学実験の提案 - 高速ビームスプリッター切替とHong-Ou-Mandel干渉を用いた検証 - 説明 (Description): [English] This paper formulates the hypothesis of "temporal bidirectionality" in quantum phenomena and proposes an experimental scheme for its verification using quantum optics. Here, temporal bidirectionality refers to the possibility that temporal degrees of freedom corresponding to both before and after a process contribute to quantum state formation and interference. Specifically, we propose an experimental setup using Mach-Zehnder and Hong-Ou-Mandel (HOM) interferometers with high-speed optical path switching at frequency f. By introducing a characteristic time scale Δt, we establish a framework to compare standard quantum mechanical predictions against temporal bidirectionality models based on the frequency dependence of interference visibility V(f) and HOM dip parameters. The primary objective of this study is not to assert the existence of temporal bidirectionality a priori, but to translate a novel hypothesis on the structure of time into a falsifiable quantum optical test. [日本語] 本論文では、量子現象における「時間前後性 (temporal bidirectionality)」という仮説を定式化し、量子光学を用いた実験的検証方法を提案する。時間前後性とは、量子状態の形成や干渉過程において、通常の因果的記述に加え、時間の前後に対応する自由度が現象に寄与する可能性を指す。 具体的には、二光路干渉計やHong-Ou-Mandel (HOM) 干渉計において、ビームスプリッター等の光路選択機構を高速(切替周波数 f)に切り替え、干渉可視度 V(f) やHOM dipの変化を測定する手法を示す。標準量子力学の予測(VSQM)と時間前後性モデルの予測(VFB)を比較し、特徴的時間スケール Δt に対応する周波数領域において生じ得る異常な周波数依存性を検証する枠組みを提示する。 本研究の目的は時間前後性の存在を事前に主張することではなく、時間の構造に関する新しい仮説を反証可能な物理モデルとして評価・検証することにある。

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Clear and rigorous quantum reasoning is needed to explain quantum physical phenomena. As pillars of true quantum physical explanations, we suggest specific quantum reasoning derived from quantum physical key ideas. An experiment is suggested to support such a quantum reasoning, in which a quantized radiation field interacts with an optical beam splitter, leading to experimental results conflicting with classical physical predictions. The results, however, can be explained consistently with a quantum reasoning based on the key ideas of probability, superposition, and interference (PSI). In this quantum optical key experiment the optical beam splitter prepares a superposition of single photon states and a Michelson interferometer is used to detect the superposition via controlled propagation phases. Although different single photon experimental setups (aimed at helping students to gain access to foundational issues in quantum physics) have been discussed in the past, the wave-particle dualism bound to classical physics maintains its predominance as an explanation pattern for the interpretation of these experiments. The study presented here investigates the effect of the quantum optical key experiment on the ability of students to use quantum reasoning based on the key ideas of PSI to overcome the naive wave-particle dualism. The current state of relevant studies that test student access to quantum physics can roughly be divided into two distinct areas: one tests how mathematical abilities help them to understand quantum physics and one tests how nonmathematical representations of a set of specific quantum theoretical traits (“Wesenszüge”) lead to a deeper understanding of quantum physics. There is a lack of questionnaires that focus on the idea of developing quantum reasoning based on superposition, probability, and interference of quantum states combined with a real experiment using true quantum light. In the first part of the article, we describe the physical modeling and present the development of the questionnaire. The set of items has been constructed from newly developed items and combined with well-tested ones. The validation of the set addresses qualitative and quantitative methods. In the second part, we give a pre- and poststudy examination of the impact of the quantum optical key experiment on students’ quantum reasoning. A significant increase in the number of students using quantum arguments is based on PSI reasoning for the explanation of an interference, such as the behavior of single photon states. Though the increase is significant, we found only minor changes in a particular issue to the students’ reasoning when approaching quantum physics as illustrated by a sample of answers given in the second part of the article. The concept of quantum states and the principle of superposition still appear particularly difficult. Published by the American Physical Society 2024

Physical Review Physics Education Research•Apr 5, 2024•11 citations
[English] This paper formulates the hypothesis of "temporal bidirectionality" in quantum phenomena and proposes an experimental scheme for its verification using quantum optics. Here, temporal bidirectionality refers to the possibility that temporal degrees of freedom corresponding to both before and after a process contribute to quantum state formation and interference. Specifically, we propose an experimental setup using Mach-Zehnder and Hong-Ou-Mandel (HOM) interferometers with high-speed optical path switching at frequency f. By introducing a characteristic time scale Δt, we establish a framework to compare standard quantum mechanical predictions against temporal bidirectionality models based on the frequency dependence of interference visibility V(f) and HOM dip parameters. The primary objective of this study is not to assert the existence of temporal bidirectionality a priori, but to translate a novel hypothesis on the structure of time into a falsifiable quantum optical test. [日本語] 本論文では、量子現象における「時間前後性 (temporal bidirectionality)」という仮説を定式化し、量子光学を用いた実験的検証方法を提案する。時間前後性とは、量子状態の形成や干渉過程において、通常の因果的記述に加え、時間の前後に対応する自由度が現象に寄与する可能性を指す。 具体的には、二光路干渉計やHong-Ou-Mandel (HOM) 干渉計において、ビームスプリッター等の光路選択機構を高速(切替周波数 f)に切り替え、干渉可視度 V(f) やHOM dipの変化を測定する手法を示す。標準量子力学の予測(VSQM)と時間前後性モデルの予測(VFB)を比較し、特徴的時間スケール Δt に対応する周波数領域において生じ得る異常な周波数依存性を検証する枠組みを提示する。 本研究の目的は時間前後性の存在を事前に主張することではなく、時間の構造に関する新しい仮説を反証可能な物理モデルとして評価・検証することにある。
説明 (Description): [English] This paper formulates the hypothesis of "temporal bidirectionality" in quantum phenomena and proposes an experimental scheme for its verification using quantum optics. Here, temporal bidirectionality refers to the possibility that temporal degrees of freedom corresponding to both before and after a process contribute to quantum state formation and interference. Specifically, we propose an experimental setup using Mach-Zehnder and Hong-Ou-Mandel (HOM) interferometers with high-speed optical path switching at frequency f. By introducing a characteristic time scale Δt, we establish a framework to compare standard quantum mechanical predictions against temporal bidirectionality models based on the frequency dependence of interference visibility V(f) and HOM dip parameters. The primary objective of this study is not to assert the existence of temporal bidirectionality a priori, but to translate a novel hypothesis on the structure of time into a falsifiable quantum optical test. [日本語] 本論文では、量子現象における「時間前後性 (temporal bidirectionality)」という仮説を定式化し、量子光学を用いた実験的検証方法を提案する。時間前後性とは、量子状態の形成や干渉過程において、通常の因果的記述に加え、時間の前後に対応する自由度が現象に寄与する可能性を指す。 具体的には、二光路干渉計やHong-Ou-Mandel (HOM) 干渉計において、ビームスプリッター等の光路選択機構を高速(切替周波数 f)に切り替え、干渉可視度 V(f) やHOM dipの変化を測定する手法を示す。標準量子力学の予測(VSQM)と時間前後性モデルの予測(VFB)を比較し、特徴的時間スケール Δt に対応する周波数領域において生じ得る異常な周波数依存性を検証する枠組みを提示する。 本研究の目的は時間前後性の存在を事前に主張することではなく、時間の構造に関する新しい仮説を反証可能な物理モデルとして評価・検証することにある。
Quantum mechanics, optics and indeed any wave theory exhibits the phenomenon of interference. In this thesis we present two problems investigating interference due to indistinguishable alternatives and a mostly unrelated investigation into the free space propagation speed of light pulses in particular spatial modes. In chapter 1 we introduce the basic properties of the electromagnetic field needed for the subsequent chapters. In chapter 2 we review the properties of interference using the beam splitter and the Mach-Zehnder interferometer. In particular we review what happens when one of the paths of the interferometer is marked in some way so that the particle having traversed it contains information as to which path it went down (to be followed up in chapter 3) and we review Hong-Ou-Mandel interference at a beam splitter (to be followed up in chapter 5). In chapter 3 we present the first of the interference problems. This consists of a nested Mach-Zehnder interferometer in which each of the free space propagation segments are weakly marked by mirrors vibrating at different frequencies [1]. The original experiment drew the conclusions that the photons followed disconnected paths. We partition the description of the light in the interferometer according to the number of paths it contains which-way information about and reinterpret the results reported in [1] in terms of the interference of paths spatially connected from source to detector. In chapter 4 we briefly review optical angular momentum, entanglement and spontaneous parametric down conversion. These concepts feed into chapter 5 in which we present the second of the interference problems namely Hong-Ou-Mandel interference with particles possessing two degrees of freedom. We analyse the problem in terms of exchange symmetry for both boson and fermion pairs and show that the particle statistics at a beam splitter can be controlled for suitably chosen states. We propose an experimental test of these ideas using orbital angular momentum entangled photons. In chapter 6 we look at the effect that the transverse spatial structure of the mode that a pulse of light is excited in has on its group velocity. We show that the resulting group velocity is slower than the speed of light in vacuum for plane waves and that this reduction in the group velocity is related to the spread in the wave vectors required to create the transverse spatial structure. We present experimental results of the measurement of this slowing down using Hong-Ou-Mandel interference.
Quantum interference forces two indistinguishable input photons to depart a beamsplitter in the same (of two possible) spatial output modes; this is known as the Hong-Ou-Mandel (HOM) effect. It provides a quantitative way of measuring the distinguishability between two photons and also has been utilised to determine their relative temporal delays [1, 2]. HOM interferometry offers numerous advantages over its classical counterpart, most importantly it lacks any dependence on the phase of the photons and therefore can potentially provide reliable measurements in environments where the phase is unstable. To date there have been very few investigations on the precision that is achievable with HOM interferometry. Experiments with collinear geometries have yielded sensitivities as low as 0.1fs however these approaches are limited to measurements of birefringence and other polarisation dependent effects [3, 4], as the precision derives from the inherently stable shared path of the photon pairs. Typical non-shared path HOM interferometers exhibit resolution of roughly 1–3 fs (0.3–1 μm).
タイトル (Title): Proposal for Quantum Optics Experiments Toward Experimental Verification of Temporal Bidirectionality: Verification Using High-Speed Beam Splitter Switching and Hong-Ou-Mandel Interference / 時間前後性の実験的検証に向けた量子光学実験の提案 - 高速ビームスプリッター切替とHong-Ou-Mandel干渉を用いた検証 - 説明 (Description): [English] This paper formulates the hypothesis of "temporal bidirectionality" in quantum phenomena and proposes an experimental scheme for its verification using quantum optics. Here, temporal bidirectionality refers to the possibility that temporal degrees of freedom corresponding to both before and after a process contribute to quantum state formation and interference. Specifically, we propose an experimental setup using Mach-Zehnder and Hong-Ou-Mandel (HOM) interferometers with high-speed optical path switching at frequency f. By introducing a characteristic time scale Δt, we establish a framework to compare standard quantum mechanical predictions against temporal bidirectionality models based on the frequency dependence of interference visibility V(f) and HOM dip parameters. The primary objective of this study is not to assert the existence of temporal bidirectionality a priori, but to translate a novel hypothesis on the structure of time into a falsifiable quantum optical test. [日本語] 本論文では、量子現象における「時間前後性 (temporal bidirectionality)」という仮説を定式化し、量子光学を用いた実験的検証方法を提案する。時間前後性とは、量子状態の形成や干渉過程において、通常の因果的記述に加え、時間の前後に対応する自由度が現象に寄与する可能性を指す。 具体的には、二光路干渉計やHong-Ou-Mandel (HOM) 干渉計において、ビームスプリッター等の光路選択機構を高速(切替周波数 f)に切り替え、干渉可視度 V(f) やHOM dipの変化を測定する手法を示す。標準量子力学の予測(VSQM)と時間前後性モデルの予測(VFB)を比較し、特徴的時間スケール Δt に対応する周波数領域において生じ得る異常な周波数依存性を検証する枠組みを提示する。 本研究の目的は時間前後性の存在を事前に主張することではなく、時間の構造に関する新しい仮説を反証可能な物理モデルとして評価・検証することにある。
Clear and rigorous quantum reasoning is needed to explain quantum physical phenomena. As pillars of true quantum physical explanations, we suggest specific quantum reasoning derived from quantum physical key ideas. An experiment is suggested to support such a quantum reasoning, in which a quantized radiation field interacts with an optical beam splitter, leading to experimental results conflicting with classical physical predictions. The results, however, can be explained consistently with a quantum reasoning based on the key ideas of probability, superposition, and interference (PSI). In this quantum optical key experiment the optical beam splitter prepares a superposition of single photon states and a Michelson interferometer is used to detect the superposition via controlled propagation phases. Although different single photon experimental setups (aimed at helping students to gain access to foundational issues in quantum physics) have been discussed in the past, the wave-particle dualism bound to classical physics maintains its predominance as an explanation pattern for the interpretation of these experiments. The study presented here investigates the effect of the quantum optical key experiment on the ability of students to use quantum reasoning based on the key ideas of PSI to overcome the naive wave-particle dualism. The current state of relevant studies that test student access to quantum physics can roughly be divided into two distinct areas: one tests how mathematical abilities help them to understand quantum physics and one tests how nonmathematical representations of a set of specific quantum theoretical traits (“Wesenszüge”) lead to a deeper understanding of quantum physics. There is a lack of questionnaires that focus on the idea of developing quantum reasoning based on superposition, probability, and interference of quantum states combined with a real experiment using true quantum light. In the first part of the article, we describe the physical modeling and present the development of the questionnaire. The set of items has been constructed from newly developed items and combined with well-tested ones. The validation of the set addresses qualitative and quantitative methods. In the second part, we give a pre- and poststudy examination of the impact of the quantum optical key experiment on students’ quantum reasoning. A significant increase in the number of students using quantum arguments is based on PSI reasoning for the explanation of an interference, such as the behavior of single photon states. Though the increase is significant, we found only minor changes in a particular issue to the students’ reasoning when approaching quantum physics as illustrated by a sample of answers given in the second part of the article. The concept of quantum states and the principle of superposition still appear particularly difficult. Published by the American Physical Society 2024