# Experimental proof of nonlocal wavefunction collapse for a single particle using homodyne measurements.

@article{Fuwa2015ExperimentalPO, title={Experimental proof of nonlocal wavefunction collapse for a single particle using homodyne measurements.}, author={Maria Fuwa and Shuntaro Takeda and Marcin Zwierz and Howard M. Wiseman and Akira Furusawa}, journal={Nature communications}, year={2015}, volume={6}, pages={ 6665 } }

A single quantum particle can be described by a wavefunction that spreads over arbitrarily large distances; however, it is never detected in two (or more) places. This strange phenomenon is explained in the quantum theory by what Einstein repudiated as 'spooky action at a distance': the instantaneous nonlocal collapse of the wavefunction to wherever the particle is detected. Here we demonstrate this single-particle spooky action, with no efficiency loophole, by splitting a single photon between…

## 92 Citations

Single-particle entanglement: Quantum nonlocality or quantum contextuality?

- Physics
- 2020

In 1927, at the Solvay conference, Einstein posed a thought experiment with the primary intention of showing the incompleteness of quantum mechanics; to prove it, he uses the instantaneous nonlocal…

Nonlocal single particle steering generated through single particle entanglement

- PhysicsScientific reports
- 2021

It is proved that the single-particle entanglement gives rise to truly nonlocal effects at two faraway places, which opens the possibility of using the single’s entangled state for implementing truly non local task.

Single-photon steering

- Physics
- 2021

According to Schrödinger, the laws of quantum mechanics obliges us to admit that by suitable measurement taken on one of the two system only the state of the other system can not only be determined…

Quantum entanglement: facts and fiction – how wrong was Einstein after all?

- PhysicsQuarterly Reviews of Biophysics
- 2016

It is proposed that photons may entangle over large distances only if some interaction exists via fields that cannot propagate faster than the speed of light, and an experiment to settle this ‘interaction hypothesis’ is suggested.

Can single photon excitation of two spatially separated modes lead to a violation of Bell inequality via weak-field homodyne measurements?

- PhysicsNew Journal of Physics
- 2021

We reconsider the all-optical weak homodyne-measurement based experimental schemes aimed at revealing Bell nonclassicality (‘nonlocality’) of a single photon. We focus on the schemes put forward by…

Microscopic Reversibility, Nonlinearity, and the Conditional Nature of Single Particle Entanglement

- Physics
- 2019

In 1935 Erwin Schrodinger [1] motivated by the famous paper [2] from Einstein, Podolsky and Rosen (EPR) comment that “Maximal knowledge of a total system does not necessarily include total knowledge…

On Nonlocality of Quantum Objects

- Physics
- 2016

We present an option of the experiment with a correlated pair of particles in the entangled state, which provides the effect of a change in the polarization for entangled photons, and demonstrate the…

The quantum Zeno effect in double well tunnelling

- Physics
- 2018

Measurement lies at the heart of quantum theory, and introductory textbooks in quantum mechanics cover the measurement problem in topics such as the Schrodinger's cat thought experiment, the EPR…

The entangled measurement state is not a paradoxical superposition of the detector

- Physics
- 2019

The entangled state that results when a detector measures a superposed quantum system has spawned decades of concern about the problem of definite outcomes or "Schrodinger's cat." This state seems to…

## References

SHOWING 1-10 OF 67 REFERENCES

Nonlocality of a single photon: Paths to an Einstein-Podolsky-Rosen-steering experiment

- Physics
- 2011

A single-photon incident on a beam splitter produces an entangled field state, and in principle could be used to violate a Bell inequality, but such an experiment (without postselection) is beyond…

Loophole-free Einstein–Podolsky–Rosen experiment via quantum steering

- Physics
- 2011

Tests of the predictions of quantum mechanics for entangled systems have provided increasing evidence against local realistic theories. However, there remains the crucial challenge of simultaneously…

Single-particle nonlocality and entanglement with the vacuum

- Physics
- 2001

We propose a single-particle experiment that is equivalent to the conventional two-particle experiment used to demonstrate a violation of Bell's inequalities. Hence, we argue that quantum mechanical…

Experimental demonstration of single photon nonlocality.

- PhysicsPhysical review letters
- 2004

This Letter experimentally implements a single photon Bell test based on the ideas of S. Tan et al. that eliminates the need for interferometrical stability in the setup, consequently making it a robust and scalable method.

The Physical Reality of the Quantum Wave Function

- Physics
- 1999

By examining a particular thought experiment, we show that two observers, outside of “each other’s light cone”, when examining the same quantum system, will ascribe very different quantum wave…

The simplest demonstrations of quantum nonlocality

- Physics
- 2011

This work investigates the complexity cost of demonstrating the key types of nonclassical correlations—Bell inequality violation, Einstein, Podolsky, Rosen (EPR)-steering, and entanglement—with independent agents, theoretically and in a photonic experiment, and exhibits a hierarchy among these three tasks.

Strong Einstein-Podolsky-Rosen entanglement from a single squeezed light source

- Physics
- 2011

Einstein-Podolsky-Rosen (EPR) entanglement is a criterion that is more demanding than just certifying entanglement. We theoretically and experimentally analyze the low-resource generation of…

Witnessing trustworthy single-photon entanglement with local homodyne measurements

- Physics2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC
- 2013

This work presents and experimentally test an entanglement witness allowing one not only to say whether a given state is path-entangled but also thatEntanglement lies in the subspace where the optical paths are each filled with one photon at most, i.e. refers to single-photon Entanglement.

Delayed-choice entanglement swapping with vacuum–one-photon quantum states

- Physics
- 2002

We report the experimental realization of a recently discovered quantum-information protocol by Peres implying an apparent nonlocal quantum mechanical retrodiction effect. The demonstration is…

Testing nonlocality of a single photon without a shared reference frame

- Physics
- 2013

The question of testing the nonlocality of a single photon has raised much debate over the last years. The controversy is intimately related to the issue of providing a common reference frame for the…