arXiv subjects

Mandip Singh

Publications and source records attributed to Mandip Singh.

At least 19 recordsLinked to original sources

arXiv2023

Quantum ghost imaging of a transparent polarisation sensitive phase pattern

A transparent polarisation sensitive phase pattern exhibits a position and polarisation dependent phase shift of transmitted light and it represents a unitary transformation. A quantum ghost image of this pattern is produced with hyper-entangled photons consisting of Einstein-Podolsky-Rosen (EPR) and polarisation entanglement. In quantum ghost imaging, a single photon interacts with the pattern and is detected by a stationary detector and a non-interacting photon is imaged on a coincidence camera. EPR entanglement manifests spatial correlations between an object plane and a ghost image plane, whereas a polarisation dependent phase shift exhibited by the pattern is detected with polarisation entanglement. In this quantum ghost imaging, the which-position-polarisation information of a photon interacting with the pattern is not present in the experiment. A quantum ghost image is constructed by measuring correlations of the polarisation-momentum of an interacting photon with polarisation-position of a non-interacting photon. The experiment is performed with a coincidence single photon detection camera, where a non-interacting photon travels a long optical path length of 17.83~$m$ from source to camera and a pattern is positioned at an optical distance of 19.16~$m$ from the camera.

quant-ph↗

arXiv2022

Nonlocal action at a distance also acts in the past

The nonlocal action of a measurement performed on a quantum entangled particle can determine the quantum state of a distant entangled particle instantly. Since the relativistic simultaneity of events is frame dependent therefore, a physically valid question arises, does the nonlocal action at a distance determine the quantum state of the distant particle in its past, when quantum state collapse is observed from a different inertial frame of reference? From the relativity of simultaneity, Lorentz invariance of the quantum entangled state of photons under consideration and the validity of Bell's theorem in all inertial frames of reference, it is demonstrated that the measurement-induced collapse of a quantum entangled state also determines the quantum state of a distant photon in its past, provided one of the photons is located in the future. The past and future are defined with respect to the time of quantum state collapse in the rest frame of a quantum state measurement device.

quant-ph↗

arXiv2021

Quantum imaging of a polarisation sensitive phase pattern with hyper-entangled photons

A transparent polarisation sensitive phase pattern makes a polarisation dependent transformation of quantum state of photons without absorbing them. Such an invisible pattern can be imaged with quantum entangled photons by making joint quantum measurements on photons. This paper shows a long path experiment to quantum image a transparent polarisation sensitive phase pattern with hyper-entangled photon pairs involving momentum and polarisation degrees of freedom. In the imaging configuration, a single photon interacts with the pattern while the other photon, which has never interacted with the pattern, is measured jointly in a chosen polarisation basis and in a quantum superposition basis of its position which is equivalent to measuring its momentum. Individual photons of each hyper-entangled pair cannot provide a complete image information. The image is constructed by measuring the polarisation state and position of the interacting photon corresponding to a measurement outcome of the non-interacting photon. This paper presents a detailed concept, theory and free space long path experiments on quantum imaging of polarisation sensitive phase patterns.

quant-ph↗

arXiv2019

Quantum diffraction of position-momentum entangled photons from a sharp edge

In this paper, an experiment of quantum diffraction of position-momentum entangled photons from a straight sharp edge is presented. Path of a single photon of an entangled pair is partially blocked by a sharp edge whereas the other photon is detected at a stationary location without revealing the which-path information of the other photon. Quantum diffraction pattern of the sharp edge is revealed only in the correlated conditional detection of spatially separated photons and no diffraction pattern is formed in local detections of individual photons. Theoretical analysis of the quantum diffraction of position-momentum entangled photons from a sharp edge is also presented in this paper. Experimental measurements of the quantum diffraction pattern are compared with theoretically calculated quantum diffraction pattern of position-momentum entangled photons.

quant-ph↗

arXiv2018

Three-dimensional imaging of a pattern localized in a phase space

In coventional imaging experiments, objects are localized in a position space and such optically responsive objects can be imaged with a convex lens and can be seen by a human eye. In this paper, we introduce an experiment on a three-dimensional imaging of a pattern which is localized in a three-dimesional phase space. The phase space pattern can not be imaged with a lens in a conventional way and it can not be seen by a human eye. In this experiment, a phase space pattern is produced from object transparancies and imprinted onto the phase space of an atomic gaseous medium, of doppler broadened absorption profile at room temperature, by utilizing velocity selective hole burning in the absorption profile. The pattern is localized in an unique three dimensional phase space which is a subspace of the six dimensional phase space. Imaging of the localized phase space pattern is performed at different momentum locations. In addition, imaging of the imprinted pattern of an object of nonuniform transmittance is presented.

quant-ph↗

arXiv2018

Intrinsic nonlinearity of a PN-junction diode and higher order harmonic generation

Voltage current characteristics of a PN-junction diode are intrinsically nonlinear in nature. It is shown in this paper that a mathematical form of nonlinearity of a PN-junction diode resembles the nonlinear response of electric polarization of a dielectric medium to the electric field. Nonlinearity of a PN-junction can be expressed in a series of successively increasing orders of the nonlinearity. For a PN-junction diode, higher order nonlinear terms become significant as a voltage across the diode is increased. In this paper, a gradual emergence of a nonlinear regime with the amplitude of a sinusoidal voltage is presented. Higher order harmonics are produced by utilizing the nonlinearity of a single PN-junction diode. An experimental realization of a frequency comb with the highest frequency up to the twentieth harmonics is also presented. In addition, in the same circuit by making the nonlinearity significant up to the second order, an experiment on generation of the sum and difference of frequencies is realized.

physics.app-ph↗

arXiv2018

Diffraction effects in mechanically chopped laser pulses

A mechanical beam chopper consists of a rotating disc of regularly spaced wide slits which allow light to pass through them. A continuous light beam, after passing through the rotating disc, is switched-on and switched-off periodically, and a series of optical pulses are produced. The intensity of each pulse is expected to rise and fall smoothly with time. However, a careful study has revealed that the edges of mechanically chopped laser light pulses consist of periodic intensity undulations which can be detected with a photo detector. It has been shown in this paper that the intensity undulations in mechanically chopped laser pulses are produced by diffraction of light from the rotating disc and a detailed explanation of the intensity undulations is given. The experiment provides an efficient method to capture a one dimensional diffraction profile of light from a straight sharp-edge in the time domain. In addition, the experiment accurately measured wavelengths of three different laser beams from the undulations in mechanically chopped laser light pulses.

physics.ins-det↗

arXiv2018

Study of normal modes and symmetry breaking in a two-dimensional pendulum

We present an experimental setup to demonstrate normal modes and symmetry breaking in a two-dimensional pendulum. In our experiment we have used two modes of a single oscillator to demonstrate normal modes, as opposed to two single oscillators used in standard setups of two-dimensional pendulums. Breaking of the cylindrical symmetry of the pendulum is achieved by attaching a spring in the suspension. This leads to interesting visual patterns in the motion, wherein the plane of the oscillator shifts with time, the motion then becomes elliptical, shifts back again to planar, before finally returning to planar motion in the original plane. The symmetry breaking leads to non-degenerate normal modes of oscillation, whose interplay gives rise to the observed motion patterns. This also explains why for a real pendulum, the plane of motion always shifts, unlike the ideal two-dimensional pendulum where the plane of oscillation is supposed to remain fixed. This curious fact also contributes to the difficulties involved in building a Foucault's pendulum, where the plane of rotation due to Coriolis force needs to be accurately measured. The strength of the symmetry breaking in our system can be quantified by a parameter the "return time", which is defined as the time over which the pendulum returns to its original motion pattern. We propose this setup as a pedagogical tool to introduce the concepts of normal modes and symmetry breaking in a physics laboratory. The motion patterns that emerge have a high visual impact and we have also described in detail the quantitative observations can be made with this setup.

physics.ed-ph↗

arXiv2017

Macroscopic quantum oscillator based on a flux qubit

In this paper a macroscopic quantum oscillator is introduced that consists of a flux qubit in the form of a cantilever. The magnetic flux linked to the flux qubit and the mechanical degrees of freedom of the cantilever are naturally coupled. The coupling is controlled through an external magnetic field. The ground state of the introduced flux-qubit-cantilever corresponds to a quantum entanglement between magnetic flux and the cantilever displacement.

quant-ph↗

arXiv2017

Quantum Stern-Gerlach experiment and path entanglement of Bose-Einstein condensate

In this paper, a quantum Stern-Gerlach thought experiment is introduced where, in addition to the intrinsic angular momentum of an atom, the magnetic field is also treated quantum mechanically. A freely falling spin polarised Bose-Einstein condensate passes close to a flux-qubit and interacts with the quantum superimposed magnetic field of the flux-qubit. Such an interaction results a macroscopic quantum entanglement of the path of a Bose-Einstein condensate with the magnetic flux quantum state of the flux-qubit. In this paper, three regimes of coupling between the flux-qubit and a freely falling Bose-Einstein condensate are discussed. The decoherence time limit required to achieve a strong coupling regime is also estimated. This paper also explores, how to produce a path entangled Bose-Einstein condensate where, the condensate can be located at physically distinct locations simultaneously. Paper provides new fundamental insights about the foundations of the quantum Stern-Gerlach experiment.

quant-ph↗

arXiv2017

Prospects for the Mass Ordering (MO) and $θ_{23}$-Octant sensitivity in LBL experiments: UNO, DUNE \& NO$ν$A

This article represents quantitative numerical analysis to find the sensitivity for the mass ordering and octant of atmospheric mixing angle $θ_{23}$ within 3$σ$ range of oscillation parameters, in the context of three long base line (LBL) accelerator experiments viz. UNO, DUNE and NO$ν$A. We notice that on the basis of quantitative sensitivity pertaining to the event rate, it is possible to investigate the mass ordering within all experiments. Conclusively, like NO$ν$A and DUNE experiments, UNO experiment stands as better alternative for investigating mass ordering, especially when we need to cross check the results at higher beam energies and base line lengths. We observe that discrete solutions viz. {\it wrong octant-right $δ_{CP}$, wrong octant-wrong $δ_{CP}$} and {\it right octant-wrong $δ_{CP}$} and continuous solutions arising due to submergence of discrete solutions with true solution are possible up to 3$σ$ level. It is UNO experiment that alone have the potential to remove these discrete solutions, while both NO$ν$A and DUNE experiments have very poor tendency to remove these discrete solutions especially near the maximal mixing. We find that these discrete solutions can be resolved up to 3$σ$ level by the combined NO$ν$A+DUNE+UNO data set, at all multiple degenerate solutions in the true parameter space considered under the study. Though replacing half the neutrino run with antineutrino run introduces qualitative advantage because of their different dependences on $δ_{CP}$, but due to lower cross section and reduction in the statistics, addition of antineutrino data make the precision worse. Thus considering experimental data only in the neutrino mode, enhances $δ_{CP}$ and $θ_{23}$ precision significantly.

hep-ph↗

arXiv2016

Studying the physics potential of long-baseline experiments in terms of new sensitivity parameters

We investigate physics opportunities to constraint leptonic CP-violation phase $δ_{CP}$ through numerical analysis of working neutrino oscillation probability parameters, in the context of long base line experiments. Numerical analysis of two parameters, the " transition probability $δ_{CP}$ phase sensitivity parameter ($A^M$) " and " CP-violation probability $δ_{CP}$ phase sensitivity parameter ($A^{CP}$) ", as function of beam energy and/or base line has been preferably carried out. It is an elegant technique to broadly analyze different experiments to constraint $δ_{CP}$ phase and also to investigate mass hierarchy in the leptonic sector. The positive and negative values of parameter $A^{CP}$ corresponding to either of hierarchy in the specific beam energy ranges, could be a very promising way to explore mass hierarchy and $δ_{CP}$ phase. The keys to more robust bounds on $δ_{CP}$ phase are improvements of the involved detection techniques to explore bit low energy and relatively long base line regions with better experimental accuracy.

hep-ph↗

arXiv2016

Neutrino mass hierarchy and δ^{CP} investigation within the biprobability (P-P^T ) plane

This article illustrates the possibility of investigating mass hierarchy and CP-violating phase δ^{CP}, in the context of CP trajectory diagrams in the bi-probability plane. Separation between normal mass hierarchy (NH) and inverted mass hierarchy (IH) CP trajectory ellipses in the P-P^T plane seems to be very promising in order to investigate mass hierarchy. Illustration of separation between two hierarchy ellipses in the E-L plane is very helping to cover all the desired base lines and beam energies and also to analyze benefits and drawbacks at single place. If we know the mass hierarchy, then from the large sizes of CP trajectory ellipse which is possible at appropriately long base line (L) and at specific value of beam energy (E), it becomes possible to investigate at-least narrow ranges of CP/T-violating phase δ^{CP}. The Possibility of more than one set of (θ_{13}; δ^{CP}) parameters to correspond to any chosen coordinate in P-P^T plane, known as parameter degeneracy, may hinder exact determination of mass hierarchy as well as δ^{CP} value. To circumvent this degeneracy in the (θ_{13}; δ^{CP}) parameter space, in case of opposite sign solutions corresponding to NH and IH case points toward the need of sufficiently long base lines, so as to separate opposite hierarchy ellipses to observable separation, and in case of same sign solutions corresponding to either NH or IH, we need to choose an experimental configuration with L = 2,535 Km, E = 5 GeV for n=1 scenario.

hep-ph↗

arXiv2015

Bose-Einstein condensate of metastable helium for quantum correlation experiments

We report on the realization of Bose-Einstein condensation of metastable helium-4. After exciting helium to its metastable state in a novel pulse-tube cryostat source, the atomic beam is collimated and slowed. We then trap several 10^8 atoms in a magneto-optical trap. For subsequent evaporative cooling, the atoms are transferred into a magnetic trap. Degeneracy is achieved with typically a few 10^6 atoms. For detection of atomic correlations with high resolution, an ultrafast delay-line detector has been installed. Consisting of four quadrants with independent readout electronics that allow for true simultaneous detection of atoms, the detector is especially suited for quantum correlation experiments that require the detection of correlated subsystems. We expect our setup to allow for the direct demonstration of momentum entanglement in a scenario equivalent to the Einstein-Podolsky-Rosen gedanken experiment. This will pave the way to matter-wave experiments exploiting the peculiarities of quantum correlations.

quant-ph↗

arXiv2014

Estimating matter induced CPT violation in Long-Baseline Neutrino Experiments

We examine matter induced CPT violation effects in long baseline electron neutrino appearance experiments in a low energy neutrino factory setup. Assuming CPT invariance in vacuum, the magnitude of CPT violating asymmetry in matter has been estimated using the exact expressions for the transition probabilities. The dependence of the asymmetry on the oscillation parameters like mixing angles, mass squared differences as well as on the Dirac CP violating phase has been investigated.

hep-ph↗

arXiv2012

Einstein-Podolsky-Rosen correlations from colliding Bose-Einstein condensates

We propose an experiment which can demonstrate quantum correlations in a physical scenario as discussed in the seminal work of Einstein, Podolsky and Rosen. Momentum-entangled massive particles are produced via the four-wave mixing process of two colliding Bose-Einstein condensates. The particles' quantum correlations can be shown in a double double-slit experiment or via ghost interference.

quant-ph↗

arXiv2009

Dynamics of reflection of ultracold atoms from a periodic 1D magnetic lattice potential

We report on an experimental study of the dynamics of the reflection of ultracold atoms from a periodic one-dimensional magnetic lattice potential. The magnetic lattice potential of period 10 \textmu m is generated by applying a uniform bias magnetic field to a microfabricated periodic structure on a silicon wafer coated with a multilayered TbGdFeCo/Cr magneto-optical film. The effective thickness of the magnetic film is about 960 nm. A detailed study of the profile of the reflected atoms as a function of externally induced periodic corrugation in the potential is described. The effect of angle of incidence is investigated in detail. The experimental observations are supported by numerical simulations.

cond-mat.other↗

arXiv2008

One dimensional lattice of permanent magnetic microtraps for ultracold atoms on an atom chip

We report on the loading and trapping of ultracold atoms in a one dimensional permanent magnetic lattice of period 10 micron produced on an atom chip. The grooved structure which generates the magnetic lattice potential is fabricated on a silicon substrate and coated with a perpendicularly magnetized multilayered TbGdFeCo/Cr film of effective thickness 960 nm. Ultracold atoms are evaporatively cooled in a Z-wire magnetic trap and then adiabatically transferred to the magnetic lattice potential by applying an appropriate bias field. Under our experimental conditions trap frequencies of up to 90 kHz in the magnetic lattice are measured and the atoms are trapped at a distance of less than 5 micron from the surface with a measured lifetime of about 450 ms. These results are important in the context of studies of quantum coherence of neutral atoms in periodic magnetic potentials on an atom chip.

physics.atom-ph↗