scholarly journals The Misuse of the No-Communication Theorem by Ghirardi - In The Analysis of a Non-Local Communication SystemThat Effectively Swaps Distant Joint Entanglement to Local Path Entanglement of an Interferometer

2019 ◽  
Author(s):  
Remi Cornwall
Keyword(s):  
Communication Systems ◽  
Single Photon ◽  
Entanglement Swapping ◽  
Schmidt Decomposition ◽  
Partial Trace ◽  
Local Communication ◽  
Two Photon ◽  
Non Local ◽  
Local Path ◽  
Joint Evolution

This paper is in response to a critique of the author’s earlier papers on the matter of a non-local communication system by Ghirardi. The setup has merit for not apparently falling for the usual pitfalls of putative communication schemes, as espoused by the No-communication theorem (NCT) - that of non-factorisability. The enquiry occurred from the investigation of two interferometer based communication systems: one two-photon entanglement, the other single-photon path entanglement. Both systems have two parties: a sender (“Alice”) who transmits or absorbs her particle and a receiver (“Bob”) who has an interferometer, which can discern a pure or mixed state, ahead of his detector. Ghirardi used the density matrix and found that the system wasn’t factorisable; this was seen as a fulfilment of the NCT. We revisit the analysis and say quite simply that Ghirardi is mistaken. The system is rendered factorisable by a Schmidt decomposition and entanglement swapping to “which path information” of the interferometer; also one must consider the joint evolution before taking the partial trace. Ghirardi’s misuse, by the inapplicability of the NCT in this situation, renders this general prohibitive bar incomplete or entirely wrong.

scholarly journals Two-photon quantum interference and entanglement at 2.1 μm

2020 ◽  
Vol 6 (13) ◽  
pp. eaay5195 ◽  
Author(s):  
Shashi Prabhakar ◽  
Taylor Shields ◽  
Adetunmise C. Dada ◽  
Mehdi Ebrahim ◽  
Gregor G. Taylor ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Communication Systems ◽  
Near Infrared ◽  
Single Photon ◽  
Satellite Communications ◽  
Optical Systems ◽  
Fiber Communication ◽  
Spectral Window ◽  
Mid Infrared ◽  
Two Photon

Quantum-enhanced optical systems operating within the 2- to 2.5-μm spectral region have the potential to revolutionize emerging applications in communications, sensing, and metrology. However, to date, sources of entangled photons have been realized mainly in the near-infrared 700- to 1550-nm spectral window. Here, using custom-designed lithium niobate crystals for spontaneous parametric down-conversion and tailored superconducting nanowire single-photon detectors, we demonstrate two-photon interference and polarization-entangled photon pairs at 2090 nm. These results open the 2- to 2.5-μm mid-infrared window for the development of optical quantum technologies such as quantum key distribution in next-generation mid-infrared fiber communication systems and future Earth-to-satellite communications.

scholarly journals Towards Heralded Two-Photon Absorption and Two-Photon Excited Fluorescence for Quantum Microscopy and Spectroscopy

2020 ◽  
Author(s):  
Andreas Jechow
Keyword(s):  
Single Photon ◽  
Entanglement Swapping ◽  
Fixed Number ◽  
Photon Absorption ◽  
Sum Frequency ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Potential Applications ◽  
Quantum Technology ◽  
Down Conversion

The interaction between single or a fixed number of photons with a single absorber is of fundamental interest in quantum technology. The harnessing of light matter interactions at the single particle limit has several potential applications ranging from quantum communication and quantum metrology to quantum imaging. In this letter, a setup for heralded two-photon absorption at the single absorber level is proposed. The setup is based on a heralded two-photon source utilizing spontaneous parametric down-conversion, entanglement swapping and sum frequency generation for joint detection. The feasibility of the scheme is discussed by reviewing recent achievements in utilizing entangled and correlated photons for two-photon absorption as well as single photon absorption experiments at the limit of single absorbers in the context of applications in imaging (here mainly microscopy) and spectroscopy.

Picosecond Single-Photon and Femtosecond Two-Photon Pulsed Laser Stimulation for IC Characterization and Failure Analysis

2009 ◽  
Author(s):  
V. Pouget ◽  
E. Faraud ◽  
K. Shao ◽  
S. Jonathas ◽  
D. Horain ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Single Photon ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Laser Stimulation ◽  
Two Photon ◽  
Resolution Improvement ◽  
Ultrashort Laser

Abstract This paper presents the use of pulsed laser stimulation with picosecond and femtosecond laser pulses. We first discuss the resolution improvement that can be expected when using ultrashort laser pulses. Two case studies are then presented to illustrate the possibilities of the pulsed laser photoelectric stimulation in picosecond single-photon and femtosecond two-photon modes.

scholarly journals Wafer-Scale Epitaxial Low Density InAs/GaAs Quantum Dot for Single Photon Emitter in Three-Inch Substrate

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 930
Author(s):  
Xiaoying Huang ◽  
Rongbin Su ◽  
Jiawei Yang ◽  
Mujie Rao ◽  
Jin Liu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Single Photon ◽  
Growth Parameters ◽  
Life Time ◽  
Correlation Factor ◽  
Low Density ◽  
Wafer Scale ◽  
Two Photon ◽  
Gaas Quantum Dot ◽  
Highly Uniform

In this work, we successfully achieved wafer-scale low density InAs/GaAs quantum dots (QDs) for single photon emitter on three-inch wafer by precisely controlling the growth parameters. The highly uniform InAs/GaAs QDs show low density of μ0.96/μm2 within the radius of 2 cm. When embedding into a circular Bragg grating cavity on highly efficient broadband reflector (CBR-HBR), the single QDs show excellent optoelectronic properties with the linewidth of 3± 0.08 GHz, the second-order correlation factor g2(τ)=0.0322 ±0.0023, and an exciton life time of 323 ps under two-photon resonant excitation.

scholarly journals Spurious poles in the scattering of electric and magnetic charges

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
John Terning ◽  
Christopher B. Verhaaren
Keyword(s):  
Perturbation Theory ◽  
Scattering Amplitudes ◽  
Pair Production ◽  
Magnetic Particles ◽  
Single Photon ◽  
Low Energy ◽  
Magnetic Interactions ◽  
Parity Conservation ◽  
Non Local ◽  
The Way

Abstract Theories with both electric and magnetic charges (“mutually non-local” theories) have several major obstacles to calculating scattering amplitudes. Even when the interaction arises through the kinetic mixing of two, otherwise independent, U(1)’s, so that all low-energy interactions are perturbative, difficulties remain: using a self-dual, local formalism leads to spurious poles at any finite order in perturbation theory. Correct calculations must show how the spurious poles cancel in observable scattering amplitudes. Consistency requires that one type of charge is confined as a result of one of the U(1)’s being broken. Here we show how the constraints of confinement and parity conservation on observable processes manages to cancel the spurious poles in scattering and pair production amplitudes, paving the way for systematic studies of the experimental signatures of “dark” electric-magnetic processes. Along the way we demonstrate some novel effects in electric-magnetic interactions, including that the amplitude for single photon production of magnetic particles by electric particles vanishes.

Two-Photon Excited Ultraviolet Photoluminescence of Zinc Oxide Nanorods

2008 ◽  
Vol 8 (11) ◽  
pp. 5854-5857 ◽  
Author(s):  
Guangping Zhu ◽  
Chunxiang Xu ◽  
Jing Zhu ◽  
Changgui Lu ◽  
Yiping Cui ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Emission Band ◽  
Single Photon ◽  
Zno Nanorods ◽  
Zinc Oxide Nanorods ◽  
Excitation Wavelength ◽  
Photoluminescence Intensity ◽  
Vapor Phase Transport ◽  
Two Photon ◽  
Oxide Nanorods

High density zinc oxide nanorods with uniform size were synthesized on (100) silicon substrate by vapor-phase transport method. The scanning electron microscopy images reveal that the nanorods have an average diameter of about 400 nm. The X-ray diffraction pattern demonstrates the wurtzite crystalline structure of the ZnO nanorods growing along [0001] direction. The single-photon excited photoluminescence presents a strong ultraviolet emission band at 394 nm and a weak visible emission band at 600 nm. When the ZnO nanorods were respectively pumped by various wavelength lasers from 520 nm to 700 nm, two-photon excited ultraviolet photoluminescence was observed. The dependence of the two-photon excited photoluminescence intensity on the excitation wavelength and power was investigated in detail.

scholarly journals Assessment of Fluorochromes for Two-Photon Laser Scanning Microscopy of Biofilms

2002 ◽  
Vol 68 (2) ◽  
pp. 901-909 ◽  
Author(s):  
Thomas R. Neu ◽  
Ute Kuhlicke ◽  
John R. Lawrence
Keyword(s):  
Nucleic Acid ◽  
Laser Scanning ◽  
Single Photon ◽  
Selective Excitation ◽  
Laser Scanning Microscopy ◽  
Scanning Microscopy ◽  
Excitation Wavelength ◽  
Laser Microscopy ◽  
Two Photon ◽  
Photon Excitation

ABSTRACT A major limitation for the use of two-proton laser scanning microscopy (2P-LSM) in biofilm and other studies is the lack of a thorough understanding of the excitation-emission responses of potential fluorochromes. In order to use 2P-LSM, the utility of various fluorochromes and probes specific for a range of biofilm constituents must be evaluated. The fluorochromes tested in this study included classical nucleic acid-specific stains, such as acridine orange (AO) and 4",6"-diamidino-2-phenylindole (DAPI), as well as recently developed stains. In addition, stains specific for biofilm extracellular polymeric substances (EPS matrix components) were tested. Two-photon excitation with a Ti/Sapphire laser was carried out at wavelengths from 760 to 900 nm in 10-nm steps. It was found that autofluorescence of phototrophic organisms (cyanobacteria and green algae) resulted in strong signals for the entire excitation range. In addition, the coenzyme F420-related autofluorescence of methanogenic bacteria could be used to obtain images of dense aggregates (excitation wavelength, 780 nm). The intensities of the emission signals for the nucleic acid-specific fluorochromes varied. For example, the intensities were similar for excitation wavelengths ranging from 780 to 900 nm for AO but were higher for a narrower range, 780 to 810 nm, for DAPI. In selective excitation, fading, multiple staining, and combined single-photon-two-photon studies, the recently developed nucleic acid-specific fluorochromes proved to be more suitable regardless of whether they are intended for living or fixed samples. Probes specific for proteins and glycoconjugates allowed two-photon imaging of polymeric biofilm constituents. Selective excitation-emission was observed for Calcofluor White M2R (780 to 800 nm) and SyproOrange (880 to 900 nm). In addition, fluor-conjugated concanavalin A lectins were examined and provided acceptable two-photon emission signals at wavelengths ranging from 780 to 800 nm. Finally, CellTracker, a fluorochrome suitable for long-term labeling of microbial eucaryote cells, was found to give strong emission at wavelengths ranging from 770 to 810 nm. If fluorochromes have the same two-photon excitation cross section, they are suitable for multiple staining and multichannel recording. Generally, if an appropriate excitation wavelength and fluorochrome were used, it was possible to obtain more highly resolved images for thick biofilm samples with two-photon laser microscopy than with conventional single-photon laser microscopy. Due to its potential for higher resolution in light-scattering tissue-like material, such as biofilms, and extremely localized excitation, 2P-LSM is a valuable addition to conventional confocal laser scanning microscopy with single-photon excitation. However, further development of the method and basic research are necessary to take full advantage of nonlinear excitation in studies of interfacial microbial ecology.

scholarly journals Optical Estimation of Absolute Membrane Potential Using One- and Two-Photon Fluorescence Lifetime Imaging Microscopy

2021 ◽  
Author(s):  
Julia R. Lazzari-Dean ◽  
Evan W. Miller
Keyword(s):  
Membrane Potential ◽  
Fluorescence Lifetime ◽  
Single Photon ◽  
Photon Counting ◽  
Fluorescence Lifetime Imaging ◽  
Single Photon Counting ◽  
Two Photon ◽  
Lifetime Imaging ◽  
Wide Range ◽  
Relative Measurements

AbstractBackgroundMembrane potential (Vmem) exerts physiological influence across a wide range of time and space scales. To study Vmem in these diverse contexts, it is essential to accurately record absolute values of Vmem, rather than solely relative measurements.Materials & MethodsWe use fluorescence lifetime imaging of a small molecule voltage sensitive dye (VF2.1.Cl) to estimate mV values of absolute membrane potential.ResultsWe test the consistency of VF2.1.Cl lifetime measurements performed on different single photon counting instruments and find that they are in striking agreement (differences of <0.5 ps/mV in the slope and <50 ps in the y-intercept). We also demonstrate that VF2.1.Cl lifetime reports absolute Vmem under two-photon (2P) illumination with better than 20 mV of Vmem resolution, a nearly 10-fold improvement over other lifetime-based methods.ConclusionsWe demonstrate that VF-FLIM is a robust and portable metric for Vmem across imaging platforms and under both one-photon and two-photon illumination. This work is a critical foundation for application of VF-FLIM to record absolute membrane potential signals in thick tissue.

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