Showing papers on "Superposition principle published in 2019"
TL;DR: A single logical qubit is encoded, manipulated and read out using a superposition of displaced squeezed states of the harmonic motion of a trapped calcium ion, which opens a route for exploring continuous variable error correction as well as hybrid quantum information schemes using both discrete and continuous variables.
Abstract: The stable operation of quantum computers will rely on error correction, in which single quantum bits of information are stored redundantly in the Hilbert space of a larger system. Such encoded qubits are commonly based on arrays of many physical qubits, but can also be realized using a single higher-dimensional quantum system, such as a harmonic oscillator1–3. In such a system, a powerful encoding has been devised based on periodically spaced superpositions of position eigenstates4–6. Various proposals have been made for realizing approximations to such states, but these have thus far remained out of reach7–11. Here we demonstrate such an encoded qubit using a superposition of displaced squeezed states of the harmonic motion of a single trapped 40Ca+ ion, controlling and measuring the mechanical oscillator through coupling to an ancillary internal-state qubit12. We prepare and reconstruct logical states with an average squared fidelity of 87.3 ± 0.7 per cent. Also, we demonstrate a universal logical single-qubit gate set, which we analyse using process tomography. For Pauli gates we reach process fidelities of about 97 per cent, whereas for continuous rotations we use gate teleportation and achieve fidelities of approximately 89 per cent. This control method opens a route for exploring continuous variable error correction as well as hybrid quantum information schemes using both discrete and continuous variables13. The code states also have direct applications in quantum sensing, allowing simultaneous measurement of small displacements in both position and momentum14,15. A single logical qubit is encoded, manipulated and read out using a superposition of displaced squeezed states of the harmonic motion of a trapped calcium ion.
177 citations
TL;DR: The proposed framework provides a method to search for the Gaussian circuit and measurement pattern that produces a target non-Gaussian state with optimal fidelity and success probability and has potential far-reaching implications for the generation of bosonic error-correction codes that require non- Gaussian states, resource states for the implementation of non-gaussian gates needed for universal quantum computation, among other applications requiring non-GAussianity.
Abstract: Generation of high-fidelity photonic non-Gaussian states is a crucial ingredient for universal quantum computation using continuous-variable platforms, yet it remains a challenge to do this efficiently. We present a general framework for a probabilistic production of multimode non-Gaussian states by measuring a few modes of multimode Gaussian states via photon-number-resolving detectors. We use Gaussian elements consisting of squeezed displaced vacuum states and interferometers, the only non-Gaussian elements consisting of photon-number-resolving detectors. We derive analytic expressions for the output Wigner function, and the probability of generating the states in terms of the mean and the covariance matrix of the Gaussian state and the photon detection pattern. We find that the output states can be written as a Fock-basis superposition state followed by a Gaussian gate, and we derive explicit expressions for these parameters. These analytic expressions show exactly what non-Gaussian states can be generated by this probabilistic scheme. Further, it provides a method to search for the Gaussian circuit and measurement pattern that produce a target non-Gaussian state with optimal fidelity and success probability. We present specific examples such as the generation of cat states, ON states, Gottesman-Kitaev-Preskill states, NOON states, and bosonic-code states. The proposed framework has potentially far-reaching implications for the generation of bosonic error-correction codes that require non-Gaussian states and resource states for the implementation of non-Gaussian gates needed for universal quantum computation, among other applications requiring non-Gaussianity. The tools developed here could also prove useful for the quantum resource theory of non-Gaussianity.
88 citations
TL;DR: In this paper, a trade-off between the need for strong gravitational effects and weak decoherence has been found for a massive quantum system in a spatial superposition, and it has been shown that such a tradeoff could be achieved in an optomechanics scenario that allows to determine whether the gravitational field generated by a quantum system generated by an infinite-dimensional superposition is in a coherent superposition or not.
Abstract: What gravitational field is generated by a massive quantum system in a spatial superposition? Despite decades of intensive theoretical and experimental research, we still do not know the answer. On the experimental side, the difficulty lies in the fact that gravity is weak and requires large masses to be detectable. However, it becomes increasingly difficult to generate spatial quantum superpositions for increasingly large masses, in light of the stronger environmental effects on such systems. Clearly, a delicate balance between the need for strong gravitational effects and weak decoherence should be found. We show that such a trade off could be achieved in an optomechanics scenario that allows to determine whether the gravitational field generated by a quantum system in a spatial superposition is in a coherent superposition or not. We estimate the magnitude of the effect and show that it offers perspectives for observability.
77 citations
TL;DR: In this article, the linear superposition principle and Hirota bilinear equations are simultaneously employed to handle two new (3+1)-dimensional Jimbo-Miwa equations, and the corresponding resonant multi-soliton solutions and the related wave numbers are formally established.
Abstract: In this paper, the linear superposition principle and Hirota bilinear equations are simultaneously employed to handle two new (3+1)-dimensional Jimbo–Miwa equations. The corresponding resonant multi-soliton solutions and the related wave numbers are formally established, which are totally different from the previously reported ones. Moreover, the extracted N-soliton waves and dispersion relations have distinct physical structures compared to solutions obtained by Wazwaz. Finally, five graphical representations are portrayed by taking definite values to free parameters which demonstrates various versions of traveling solitary waves. The results show the proposed approach provides enough freedom to construct multi-soliton waves that may be related to a large variety of real physical phenomena and, moreover, enriches the solution structure.
65 citations
TL;DR: It is shown that, the generated non-locality correlations crucially depend on the decay and the initial coherence intensity of the cavity field, and the phenomena of sudden birth and death entanglement are found.
Abstract: We analytically investigate two separated qubits inside an open cavity field. The cavity is initially prepared in a superposition coherent state. The non-locality correlations [including trace norm measurement induced non-locality, maximal Bell-correlation, and concurrence entanglement] of the two qubits are explored. It is shown that, the generated non-locality correlations crucially depend on the decay and the initial coherence intensity of the cavity field. The enhancement of the initial coherence intensity and its superposition leads to increasing the generated non-locality correlations. The phenomena of sudden birth and death entanglement are found.
63 citations
TL;DR: In this article, the authors present analytical and numerical results on the formation and properties of the leaky stop band in one-dimensional photonic lattices, where one band edge mode suffers radiation loss generating guided-mode resonance whereas the other band edge becomes a non-leaky bound-state in the continuum.
Abstract: We present analytical and numerical results on the formation and properties of the leaky stop band in one-dimensional photonic lattices. At the second stop band, one band edge mode suffers radiation loss generating guided-mode resonance whereas the other band edge mode becomes a non-leaky bound-state in the continuum. We show that the frequency location of the leaky band edge, and correspondingly the bound-state edge, is determined by superposition of Bragg processes generated by the first two Fourier harmonics of the spatial dielectric constant modulation. At the closed-band state, we discover an analytic condition for the exceptional point where frequency is fully degenerate.
62 citations
TL;DR: In this paper, pure two-bubbles are constructed for energy-critical wave equations, that is solutions which in one time direction approach a superposition of two stationary states both centered at the origin, but asymptotically decoupled in scale.
Abstract: We construct pure two-bubbles for some energy-critical wave equations, that is solutions which in one time direction approach a superposition of two stationary states both centered at the origin, but asymptotically decoupled in scale. Our solution exists globally, with one bubble at a fixed scale and the other concentrating in infinite time, with an error tending to 0 in the energy space. We treat the cases of the power nonlinearity in space dimension 6, the radial Yang-Mills equation and the equivariant wave map equation with equivariance class k > 2. The concentrating speed of the second bubble is exponential for the first two models and a power function in the last case.
54 citations
TL;DR: In this paper, the authors show that when a system with a strong symmetry is initialized in a quantum superposition involving several of these sectors, each individual stochastic trajectory will randomly select a single one of them and remain there for the rest of the evolution.
Abstract: In driven-dissipative systems, the presence of a strong symmetry guarantees the existence of several steady states belonging to different symmetry sectors. Here we show that when a system with a strong symmetry is initialized in a quantum superposition involving several of these sectors, each individual stochastic trajectory will randomly select a single one of them and remain there for the rest of the evolution. Since a strong symmetry implies a conservation law for the corresponding symmetry operator on the ensemble level, this selection of a single sector from an initial superposition entails a breakdown of this conservation law at the level of individual realizations. Given that such a superposition is impossible in a classical stochastic trajectory, this is a a purely quantum effect with no classical analog. Our results show that a system with a closed Liouvillian gap may exhibit, when monitored over a single run of an experiment, a behavior completely opposite to the usual notion of dynamical phase coexistence and intermittency, which are typically considered hallmarks of a dissipative phase transition. We discuss our results on a coherently driven spin ensemble with a squeezed superradiant decay, a simple model that presents a wealth of nonergodic dynamics.
54 citations
TL;DR: In this article, a quantum coherent superposition of different energy states of an electron wave function is used to reconstruct the amplitude and phase of a signal in an ultrafast transmission electron microscope (UEM).
Abstract: Holography relies on the interference between a known reference and a signal of interest to reconstruct both the amplitude and the phase of that signal. With electrons, the extension of holography to the ultrafast time domain remains a challenge, although it would yield the highest possible combined spatiotemporal resolution. Here, we show that holograms of local electromagnetic fields can be obtained with combined attosecond/nanometer resolution in an ultrafast transmission electron microscope (UEM). Unlike conventional holography, where signal and reference are spatially separated and then recombined to interfere, our method relies on electromagnetic fields to split an electron wave function in a quantum coherent superposition of different energy states. In the image plane, spatial modulation of the electron energy distribution reflects the phase relation between reference and signal fields. Beyond imaging applications, this approach allows implementing quantum measurements in parallel, providing an efficient and versatile tool for electron quantum optics.
50 citations
TL;DR: In this article, the authors report the on-demand generation of quantum superpositions of zero, one and two photons via coherent control of an artificial atom via coherent excitation with a resonant laser.
Abstract: Generating light in a pure quantum state is essential for advancing optical quantum technologies. However, controlling its photon number remains elusive. Optical fields with zero and one photon can be produced by single atoms, but, so far, this has been limited to generating incoherent mixtures or coherent superpositions with a very small one-photon term. Here, we report the on-demand generation of quantum superpositions of zero, one and two photons via coherent control of an artificial atom. Driving the system up to full atomic inversion leads to quantum superpositions of vacuum and one photon, with their relative populations controlled by the driving laser intensity. A stronger driving of the system, with 2π pulses, results in a coherent superposition of vacuum, one and two photons, with the two-photon term exceeding the one-photon component, a state allowing phase super-resolving interferometry. Our results open new paths for optical quantum technologies with access to the photon-number degree of freedom. Following excitation with a resonant laser, on-demand generation of non-classical light states in photon-number superpositions of zero-, one- and two-photon Fock states is demonstrated from a GaAs-based cavity containing InAs quantum dots.
48 citations
TL;DR: In this paper, the electronic spin of a single nitrogen-vacancy impurity is employed to control the coherent coupling between the mechanical modes of two carbon nanotubes and demonstrate that a mechanical phonon can be in a coherent superposition of wave and particle.
Abstract: We present and analyze a proposal for a macroscopic quantum delayed-choice experiment with massive mechanical resonators. In our approach, the electronic spin of a single nitrogen-vacancy impurity is employed to control the coherent coupling between the mechanical modes of two carbon nanotubes. We demonstrate that a mechanical phonon can be in a coherent superposition of wave and particle, thus exhibiting both behaviors at the same time. We also discuss the mechanical noise tolerable in our proposal and predict a critical temperature below which the morphing between wave and particle states can be effectively observed in the presence of environment-induced fluctuations. Furthermore, we describe how to amplify single-phonon excitations of the mechanical-resonator superposition states to a macroscopic level, via squeezing the mechanical modes. This approach corresponds to the phase-covariant cloning. Therefore, our proposal can serve as a test of macroscopic quantum superpositions of massive objects even with large excitations. This work, which describes a fundamental test of the limits of quantum mechanics at the macroscopic scale, would have implications for quantum metrology and quantum information processing.
TL;DR: In this article, a superposition-based coupling of peridynamics and finite element method (FEM) for static and quasi-static problems is developed, which is based on partial superposition of nonlocal PD and local FEM solutions subjected to appropriate homogeneous boundary conditions that enforce solution continuity.
Abstract: A superposition-based coupling of peridynamics (PD) and finite element method (FEM) for static and quasi-static problems is developed. The proposed coupling approach is based on partial superposition of nonlocal PD and local FEM solutions subjected to appropriate homogeneous boundary conditions that enforce solution continuity. The noteworthy features of the proposed PD–FEM superposition approach are: (1) it is free of blending parameters and (2) it preserves the standard computational structure of its two constituents, i.e., discrete weak form of the FEM and the strong form mesh-free style of PD. The performance of the proposed superposition approach is studied for several one- and two- dimensional problems.
TL;DR: In this article, the performance of different multiplexing methods (coherent superposition or incoherence superposition) and de-multiplexing method (2-D Dammann fork grating (DFG) and MPH) of vortex beams are discussed.
TL;DR: All-electronic suppression of transport in a carbon nanotube originating from coherent population trapping is found and criteria for the presence of such a dark state is given.
Abstract: Illumination of atoms by resonant lasers can pump electrons into a coherent superposition of hyperfine levels which can no longer absorb the light. Such superposition is known as a dark state, because fluorescent light emission is then suppressed. Here we report an all-electric analogue of this destructive interference effect in a carbon nanotube quantum dot. The dark states are a coherent superposition of valley (angular momentum) states which are decoupled from either the drain or the source leads. Their emergence is visible in asymmetric current-voltage characteristics, with missing current steps and current suppression which depend on the polarity of the applied source-drain bias. Our results demonstrate coherent-population trapping by all-electric means in an artificial atom.
TL;DR: In this article, a single-photon emitter was constructed from a two-level system (2LS) ultrastrongly coupled to a finite-band waveguide in a vacuum state.
Abstract: Heisenberg's uncertainty principle implies that the quantum vacuum is not empty but fluctuates. These fluctuations can be converted into radiation through nonadiabatic changes in the Hamiltonian. Here, we discuss how to control this vacuum radiation, engineering a single-photon emitter out of a two-level system (2LS) ultrastrongly coupled to a finite-band waveguide in a vacuum state. More precisely, we show the 2LS nonlinearity shapes the vacuum radiation into a non-Gaussian superposition of even and odd cat states. When the 2LS bare frequency lays within the band gaps, this emission can be well approximated by individual photons. This picture is confirmed by a characterization of the ground and bound states, and a study of the dynamics with matrix-product states and polaron Hamiltonian methods.
TL;DR: This work experimentally demonstrates distillation of a quantum image from measured data composed of a superposition of both quantum and classical light and provides a method to mix and distinguish information carried by quantum and Classical light, which may be useful for quantum imaging, communications, and security.
Abstract: Imaging with quantum states of light promises advantages over classical approaches in terms of resolution, signal-to-noise ratio, and sensitivity. However, quantum detectors are particularly sensitive sources of classical noise that can reduce or cancel any quantum advantage in the final result. Without operating in the single-photon counting regime, we experimentally demonstrate distillation of a quantum image from measured data composed of a superposition of both quantum and classical light. We measure the image of an object formed under quantum illumination (correlated photons) that is mixed with another image produced by classical light (uncorrelated photons) with the same spectrum and polarization, and we demonstrate near-perfect separation of the two superimposed images by intensity correlation measurements. This work provides a method to mix and distinguish information carried by quantum and classical light, which may be useful for quantum imaging, communications, and security.
TL;DR: In this paper, the authors considered transfer of optical vortices between laser pulses carrying orbital angular momentum in a cloud of cold atoms characterized by the atom-light coupling and showed that the absorption of the incident probe beam takes place mostly at the beginning of the atomic medium within the absorption length.
Abstract: We consider transfer of optical vortices between laser pulses carrying orbital angular momentum in a cloud of cold atoms characterized by the $\mathrm{\ensuremath{\Lambda}}$ configuration of the atom-light coupling. The atoms are initially prepared in a coherent superposition of the lower levels, creating a so-called phaseonium medium. If a single vortex beam initially acts on one transition of the scheme, an extra laser beam is subsequently generated with the same vorticity as that of the incident vortex beam. The absorption of the incident probe beam takes place mostly at the beginning of the atomic medium within the absorption length. The losses disappear as the probe beam propagates deeper into the medium where the atoms are transferred to their dark states. The method is extended to a tripod atom-light coupling scheme and a more general ($n+1$)-level scheme containing $n$ ground states and one excited state, allowing for creation of multiple twisted light beams. We also analyze generation of composite optical vortices in the scheme using a superposition of two initial vortex beams and study lossless propagation of such composite vortices.
TL;DR: In this article, a non-reciprocal dispersion diagram is computed using a generalized plane wave expansion method, whose formulation, provided in the paper, is able to describe how a generic discrete or continuous unit cell was able to break the mirror symmetry in the momentum space.
TL;DR: In this paper, a half-metre wide ellipsoid filled with water is brought to solid-body rotation, and then undergoes sustained harmonic modulation of its rotation rate, triggering the exponential growth of a pair of inertial waves via a mechanism called the libration-driven elliptical instability.
Abstract: In this paper, we present an experimental investigation of the turbulent saturation of the flow driven by the parametric resonance of inertial waves in a rotating fluid. In our setup , a half-metre wide ellipsoid filled with water is brought to solid-body rotation, and then undergoes sustained harmonic modulation of its rotation rate. This triggers the exponential growth of a pair of inertial waves via a mechanism called the libration-driven elliptical instability. Once the saturation of this instability is reached, we observe a turbulent state for which energy is injected into the resonant inertial waves only. Depending on the amplitude of the rotation rate modulation, two different saturation states are observed. At large forcing amplitudes, the saturation flow mainly consists of a steady, geostrophic anticyclone. Its amplitude vanishes as the forcing amplitude is decreased while remaining above the threshold of the elliptical instability. Below this secondary transition, the saturation flow is a superposition of inertial waves which are in weakly nonlinear resonant interaction, a state that could asymptotically lead to inertial wave turbulence. In addition to being a first experimental observation of a wave-dominated saturation in unstable rotating flows, the present study is also an experimental confirmation of the model of Le Reun et al. (Phys. Rev. Lett., vol. 119 (3), 2017, 034502) who introduced the possibility of these two turbulent regimes. The transition between these two regimes and their relevance to geophysical applications are finally discussed.
TL;DR: The multiphoton Jaynes-Cummings model is investigated and applications in quantum information science are explored and a Fock state filter, or quantum scissor, is implemented that restricts the dynamics of a given bosonic mode to a limited Hilbert space.
Abstract: The multiphoton Jaynes-Cummings model is investigated and applications in quantum information science are explored Considering the strong atom-field coupling regime and an $N$-photon interaction, a nonlinear driving field can perform an arbitrary rotation in the Fock space of a bosonic mode involving the vacuum and an $M$-Fock state, with $MlN$ In addition, driving a bosonic mode with a linear coherent field (superposition of many Fock states), only the cavity states within the Fock subspace ${|0⟩,|1⟩,\dots{},|N\ensuremath{-}1⟩}$ can be populated; ie, we show how to implement a Fock state filter, or quantum scissor, that restricts the dynamics of a given bosonic mode to a limited Hilbert space Such a device can be employed as a generator of finite-dimensional quantum-optical states and also as a quantum-optical intensity limiter, allowing as a special case the generation of single-photon pulses On the other hand, our system also provides a very rich physics in the weak atom-field coupling regime, in particular, multiphoton electromagnetically induced transparencylike phenomena, inducing a narrow (controllable) reflectivity window for nonlinear probe fields These results are useful for applications in quantum information processing and also motivate further investigations, eg, the use of an $N$-photon Jaynes-Cummings system as a qudit with harmonic spectrum and the exploration of multiphoton quantum interference
TL;DR: In this paper, an extension of the strong field approximation (SFA) is proposed to incorporate nondipole contributions in the interaction between the photoelectron and the driving laser field. And the authors derive Volkov-type continuum wave functions of an electron propagating in a laser field of arbitrary spatial dependence, which are also appropriate to deal with more complex laser fields like twisted Bessel or Laguerre-Gaussian beams.
Abstract: The strong-field approximation (SFA) is widely used to theoretically describe the ionization of atoms and molecules in intense laser fields. We here propose an extension of the SFA to incorporate nondipole contributions in the interaction between the photoelectron and the driving laser field. To this end, we derive Volkov-type continuum wave functions of an electron propagating in a laser field of arbitrary spatial dependence. Based on previous work by L. Rosenberg and F. Zhou [Phys. Rev. A 47, 2146 (1993)], we show how to construct such Volkov-type solutions to the Schr\"odinger equation for an electron in a vector potential that can be written as an integral superposition of plane waves. These solutions are therefore not restricted to plane waves but are also appropriate to deal with more complex laser fields like twisted Bessel or Laguerre-Gaussian beams, where the magnetic field plays an important role. As an example, we compute photoelectron spectra in the above-threshold ionization of atoms with a single-mode plane-wave laser field of midinfrared wavelength. Especially, we demonstrate how peak offsets in the ${p}_{z}$ direction can be extracted that result from the nondipole nature of the interaction. Here, we find good agreement with previous theoretical and experimental studies for circular polarization and discuss differences for linear polarization.
TL;DR: In this paper, the Hamiltonian system-based symplectic superposition method was used to solve the non-Levy-type cylindrical shell panels. But the main advantage of the developed approach is that no pre-determination of solution forms is needed, which enables one to pursue more analytic solutions of intractable shell problems.
TL;DR: In this paper, a massive quantum body is put into a spatial superposition, and it is of interest to consider the quantum aspects of the gravitational field sourced by the body, in order to understa...
Abstract: When a massive quantum body is put into a spatial superposition, it is of interest to consider the quantum aspects of the gravitational field sourced by the body. We argue that in order to understa...
29 Oct 2019
TL;DR: In this paper, a genetic algorithm was proposed to find quantum states with a large quantum Fisher information (QFI), which can be seen as Schrodinger-cat-like states.
Abstract: We introduce a genetic algorithm that designs quantum optics experiments for engineering quantum states with specific properties. Our algorithm is powerful and flexible, and can easily be modified to find methods of engineering states for a range of applications. Here we focus on quantum metrology. First, we consider the noise-free case, and use the algorithm to find quantum states with a large quantum Fisher information (QFI). We find methods, which only involve experimental elements that are available with current or near-future technology, for engineering quantum states with up to a 100-fold improvement over the best classical state, and a 20-fold improvement over the optimal Gaussian state. Such states are a superposition of the vacuum with a large number of photons (around 80), and can hence be seen as Schrodinger-cat-like states. We then apply the two most dominant noise sources in our setting -- photon loss and imperfect heralding -- and use the algorithm to find quantum states that still improve over the optimal Gaussian state with realistic levels of noise. This will open up experimental and technological work in using exotic non-Gaussian states for quantum-enhanced phase measurements. Finally, we use the Bayesian mean square error to look beyond the regime of validity of the QFI, finding quantum states with precision enhancements over the alternatives even when the experiment operates in the regime of limited data.
TL;DR: In this paper, the authors applied the modified Fourier series method to investigate the sound-vibration characteristics by establishing a composite laminated thin sector plate-cavity coupled model for the first time based on the classical plate theory (CPT) and Rayleigh-Ritz energy technique.
TL;DR: In this paper, a statistical theory of rogue waves is proposed and tested against experimental data collected in a long water tank where random waves with different degrees of nonlinearity are mechanically generated and free to propagate along the flume.
Abstract: A statistical theory of rogue waves is proposed and tested against experimental data collected in a long water tank where random waves with different degrees of nonlinearity are mechanically generated and free to propagate along the flume. Strong evidence is given that the rogue waves observed in the tank are hydrodynamic instantons, that is, saddle point configurations of the action associated with the stochastic model of the wave system. As shown here, these hydrodynamic instantons are complex spatio-temporal wave field configurations, which can be defined using the mathematical framework of Large Deviation Theory and calculated via tailored numerical methods. These results indicate that the instantons describe equally well rogue waves that originate from a simple linear superposition mechanism (in weakly nonlinear conditions) or from a nonlinear focusing one (in strongly nonlinear conditions), paving the way for the development of a unified explanation to rogue wave formation.
TL;DR: This work relies on the superposition principle, which enables the splitting of the input beam into identical copies, allowing the simultaneous measurement of all intensities, to reliably reconstruct the SoP with high fidelity and at speeds of up to 27 Hz, paving the way for real-time polarimetry of structured light.
Abstract: Stokes polarimetry (SP) is a powerful technique that enables spatial reconstruction of the state of polarization (SoP) of a light beam using only intensity measurements. A given SoP is reconstructed from a set of four Stokes parameters, which are computed through four intensity measurements. Since all intensities must be performed on the same beam, it is common to record each intensity individually, one after the other, limiting its performance to light beams with static SoP. Here, we put forward a novel technique to extend SP to a broader set of light beams with dynamic SoP. This technique relies on the superposition principle, which enables the splitting of the input beam into identical copies, allowing the simultaneous measurement of all intensities. For this, the input beam is passed through a multiplexed digital hologram displayed on a polarization-insensitive Digital Micromirror Device (DMD) that grants independent and rapid (20 kHz) manipulation of each beam. We are able to reliably reconstruct the SoP with high fidelity and at speeds of up to 27 Hz, paving the way for real-time polarimetry of structured light.
01 Nov 2019
TL;DR: In this article, a single atom in a superposition of two circular Rydberg states with huge opposite magnetic momenta is reported and demonstrated to be an extremely sensitive probe of the magnetic field, able to perform a single-shot detection of a 13 nT field in only 20μs.
Abstract: Superpositions of states with macroscopically different properties, named ‘cats’ after Schrodinger’s Gedanken experiment, are extraordinarily sensitive probes of their environment. They can be used to investigate the decoherence mechanism and the quantum-to-classical transition1–5, as well as to realize quantum-enabled sensors6 with promising applications. We report here the creation of a ‘circular cat’, namely an atom in a superposition of two circular Rydberg states with huge opposite magnetic momenta. It is an exquisite probe of the magnetic field, able to perform a single-shot detection of a 13 nT field in only 20 μs. This single-atom cat is as sensitive as a set of 1,800 ordinary atoms, demonstrating the usefulness of Rydberg state engineering for quantum-enabled technologies. An atom in a superposition of two circular Rydberg states with huge opposite magnetic momenta is reported and demonstrated to be an extremely sensitive probe of the magnetic field.