Imaginary Counterpart Research Articles

Fast topological pumps via quantum metric engineering on photonic chips.

Topological pumps have garnered substantial attention in physics. However, the requirement for slow evolution speed to satisfy adiabaticity greatly restricts their application in on-chip devices. Here, we discover a direct link between adiabaticity and quantum metric, the real part of quantum geometry that has been relatively less explored compared to its imaginary counterpart, the Berry curvature. We demonstrate that the evolution speed of topological pumps between nontrivial edge states can be increased by reducing the quantum metric via introduction of long-range coupling to the celebrated Rice-Mele model. This fast topological pump can occur without affecting the bulk state evolution, which challenges the common understanding. We experimentally confirm our findings by using a platform consisting of bilayer integrated silicon waveguides operating at telecommunication wavelengths. Our work provides possibilities for lifting topological pumps from the constraints of slow evolution and paves the way toward compact photonic integration.

The impact of ROI extraction method for MEG connectivity estimation: Practical recommendations for the study of resting state data.

Magnetoencephalography and electroencephalography (M/EEG) seed-based connectivity analysis typically requires regions of interest (ROI)-based extraction of measures. M/EEG ROI-derived source activity can be treated in different ways. For instance, it is possible to average each ROI's time series prior to calculating connectivity measures. Alternatively one can compute connectivity maps for each element of the ROI, prior to dimensionality reduction to obtain a single map. The impact of these different strategies on connectivity estimation is still unclear.Here, we address this question within a large MEG resting state cohort (N=113) and simulated data. We consider 68 ROIs (Desikan-Kiliany atlas), two measures of connectivity (phase locking value-PLV, and its imaginary counterpart- ciPLV), and three frequency bands (theta 4-8 Hz, alpha 9-12 Hz, beta 15-30 Hz). We consider four extraction methods: (i) mean, or (ii) PCA of the activity within the ROI before computing connectivity, (iii) average, or (iv) maximum connectivity after computing connectivity for each element of the seed. Connectivity outputs from these extraction strategies are then compared with hierarchical clustering, followed by direct contrasts across extraction methods. Finally, the results are validated by using a set of realistic simulations.We show that ROI-based connectivity maps vary remarkably across strategies in both connectivity magnitude and spatial distribution. Dimensionality reduction procedures conducted after computing connectivity are more similar to each-other, while PCA before approach is the most dissimilar to other approaches. Although differences across methods are consistent across frequency bands, they are influenced by the connectivity metric and ROI size. Greater differences were observed for ciPLV than PLV, and in larger ROIs. Realistic simulations confirmed that after aggregation procedures are generally more accurate but have lower specificity (higher rate of false positive connections). Although computationally demanding, after dimensionality reduction strategies should be preferred when higher sensitivity is desired. Given the remarkable differences across aggregation procedures, caution is warranted in comparing results across studies applying different extraction methods.

AN OVERVIEW ON ROBOTICS AND CONTROL SYSTEMS

A robot is a virtual or mechanical agent. In practice, it is often an electro-mechanical system, which looks and speeds as if it were one of its own. The intent and its own agency. The term robot refers to both physical robots and virtual software agents, but often virtual software agents are called bots. There has been no consensus that machines are qualified as robots, but there is a consensus among experts and the public that some or all of the following can be done such as: walking, operating a device or a component of the environment, the environment Understanding and manipulating it and imparting intelligent behavior that mimics human and animal behaveor. The stories of artificial assistants and companions and and the effort to create them have a long history, but fully autonomous machines were the only programmed first robot to run in the digital system since the 20th century, Unimate, In 1971, hot pieces of metal were picked up from the stamp making machine and made to make their stack. Today, commercial and industrial robots are widely used inexpensively and with greater accuracy and greater reliability than humans. They are also employed for tasks which are very dangerous in human terms. , Messy and boring tasks. Robots are being widely used for manufacturing, assembly and bundling, transportation, earth and space exploration, surgery, weapons manufacturing, laboratory research and consumer and industrial production. Domestic robots are generally common around homes for cleaning and maintenance work. Concerns about the economic impact of robotic weapons and automation are generally common. Remains, a concern that is not resolved by the villainous, intelligent, acrobatic robots described in popular entertainment. Real robots are still benign, retarded, and gross compared to their imaginary counterparts.

Les théories du complot : l’envers du mythe totémique dans le lien social

ObjectivesThe current explosion of conspiracy theories is an undeniable dimension of present-day social bonds. We aim to understand some of the unconscious stakes underlying the conspiratorial ideation and to shed light upon the reasons why it is a topical issue in our modern society. MethodsBy relying on psychoanalytical knowledge that allows us to study the psychic functions of the myth, we will compare different conspiracy formations to those of the mythical narrative to bring into resonance these two fictional modalities. Freud's totemic myth, through its structure, sheds a particular light on the functions that regulate jouissance and that organize history, as well as social bonds. ResultsThe conspiracy discourse will prove to be the underside of the Freudian myth of Totem and Taboo. The text presenting the myth of the primal horde will reveal the structure of the conspiracy discourse as its negative. Indeed, this myth offers a symbolic ur-fiction, and its imaginary counterpart determines the conspiratorial grammar based on the question: “who profits from the crime?” As in a hall of mirrors, the countless conspiracies will appear as the shadow of a crime, always returning in an imaginary mode due to a lack of symbolization. The system that the conspiracy theory seeks to unveil will then be regarded as the reverse of an arrangement structured by the myth. DiscussionWe discuss the link between scientific discourse and the intensification of conspiracy theories’ presence in our modern society. Indeed, Lacan notices how the mythical dimension is repressed by scientific discourse. Such repression would produce, as a result, imaginary versions of the myth. Thus, the conspiracy theory will be regarded as a structural effect of scientific discourse rather than as anti-science. ConclusionsThe conspiracy theory turns out to be a social symptom linked to scientific discourse. It is the social staging of damage suffered that transforms the coordinates of a symbolic loss, no longer organized by a myth, into an imaginary stolen jouissance.

Azimuthal Imaginary Poynting Momentum Density.

The momentum of light beams can possess azimuthal densities, circulating around the beam axis and inducing intriguing mechanical effects in local light-matter interaction. Belinfante's spin momentum loops in circularly polarized beams, while the canonical momentum spirals in helically phased beams. However, a similar behavior of their imaginary counterpart, the so-called imaginary Poynting momentum (IPM), has not yet emerged. The foremost purpose of the present work is to put forward the discovery of this IPM vortex. We show that a simple superposition of radially and azimuthally polarized beams can form an IPM of completely azimuthal density. Additionally, the azimuthal IPM density can exist with a donut beam-intensity distribution and even with a vanishing azimuthal component of all other momenta. This uncovers the existence of a new mechanical effect which broadens the area of optical micromanipulation by achieving optical rotation of isotropic spheres, in the absence of both spin and orbital angular momenta. Our findings enrich the local dynamic properties of electromagnetic fields, highlighting the rotational action of their IPM, and thus its mechanical effect on microparticles and nanoparticles.

Hypothesis Falsification in the 2-4-6 Number Sequence Test: Introducing Imaginary Counterparts

Two main cognitive theories predict that people find refuting evidence that falsifies their theorising difficult, if not impossible to consider, even though such reasoning may be pivotal to grounding their everyday thoughts in reality (i.e., Poletiek, 1996; Klayman & Ha, 1987). In the classic 2-4-6 number sequence task devised by psychologists to test such reasoning skills in a simulated environment – people fail the test more often than not. In the 2-4-6 task participants try to discover what rule the number triple 2-4-6 conforms to. The rule is ‘ascending numbers’, but it is tricky to discover this rule. Participants tend to generate hypotheses with the properties of the 2-4-6 triple, for example, ‘even numbers ascending in twos’. They must search for evidence to test whether their hypothesis is the rule. But experimental evidence has shown that they tend to generate confirming triples that they expect to be consistent with their hypothesis rather than inconsistent falsifying triples. Counter to the two main hypothesis testing theories this paper demonstrates that falsification is possible in five 2-4-6 task experiments when participants consider an Imaginary Participant’s hypothesis. Experiment 1 and 2 show that competition with an opponent hypothesis tester facilitates falsification. Experiments 3 to 5 show that the consideration of an alternative hypothesis helps this falsification of hypotheses lead to rule discovery. The implications of the results for theories of hypothesis testing and reasoning are discussed.

Hilbert transform: Applications to atomic spectra

In many areas of physics, the Kramers-Kronig (KK) relations are used to extract information about the real part of the optical response of a medium from its imaginary counterpart. In this paper we discuss an alternative but mathematically equivalent approach based on the Hilbert transform. We apply the Hilbert transform to transmission spectra to find the group and refractive indices of a Cs vapor, and thereby demonstrate how the Hilbert transform allows indirect measurement of the refractive index, group index and group delay whilst avoiding the use of complicated experimental set ups.

Efficient dealing with spectrum line profiles using complex rational functions

We comment on the use of complex rational functions in dealing with spectrum line profiles. This involves efficient ways of computation of the profiles, as well as applications in describing the real and imaginary counterparts of response functions, obeying Kramers–Kronig relations.

Sibling curves 3: imaginary siblings and tracing complex roots

Visualizing complex roots of a quadratic equation has been a quest since the inception of the Argand plane in the 1800s. Many algebraic and numerical methods exist for calculating complex roots of an equation, but few visual methods exist. Following on from papers by Harding and Engelbrecht (A. Harding and J. Engelbrecht, Sibling curves and complex roots 1: looking back, Int. J. Math. Educ. Sci. Technol. 38(7) (2007), pp. 963–974; A. Harding and J. Engelbrecht, Sibling curves and complex roots 2: looking ahead, Int. J. Math. Educ. Sci. Technol. 38(7) (2007), pp. 975–985), where the existence and properties of sibling curves for the well-known functions were described, we introduce imaginary sibling curves. We then focus on the domain curves of siblings and their imaginary counterparts to trace and visualize the complex roots.

Explicit infrastructure for real quadratic function fields and real hyperelliptic curves

In 1989, Koblitz first proposed the Jacobian of a an imaginary hyperelliptic curve for use in public-key cryptographic proto- cols. This concept is a generalization of elliptic curve cryptography. It can be used with the same assumed key-per-bit strength for small genus. More recently, real hyperelliptic curves of small genus have been introduced as another source for cryptographic protocols. The arithmetic is more in- volved than its imaginary counterparts and it is based on the so-called infrastructure of the set of reduced principal ideals in the ring of regular functions of the curve. This infrastructure is an interesting phenomenon. The main purpose of this article is to explain the infrastructure in explicit terms and thus extend Shanks' infrastructure ideas in real quadratic num- ber fields to the case of real quadratic congruence function fields and their curves. Hereby, we first present an elementary introduction to the contin- ued fraction expansion of real quadratic irrationalities and then generalize important results for reduced ideals.

The imaginary counterpart of recorded motions

AbstractIn this paper it is shown that any recorded motion has an imaginary counterpart. Starting from the harmonic input motion where the sine function is the imaginary counterpart of the cosine function, it is shown that all time histories exist in pairs. The imaginary counterpart of records is not needed when the response of a system is described by a real‐parameter constitutive model. However, it is shown that when complex‐parameter models are used, the imaginary counterpart of records has equal importance as the real‐valued record and in this case the input motion should be strictly complex valued. The procedure to construct the imaginary counterpart of any piecewise continuous record is developed. A constructed complex‐valued earthquake time history is used as input motion to a system described by a Kelvin model with complex damping constant. The validity of the procedure is demonstrated by comparing the response of the complex‐damping Kelvin model against the results obtained from a mathematically equivalent real‐valued formulation.

Self-energies of nuclei and real and imaginary optical model potentials.

Previously the inverse mean field method has been shown to lead to an analytical expression for the volume integral J/sub V/(A) per nucleon over the self-energies of nuclei with mass numbers A and to specific energy dependences for real f(E/sub p/) and imaginary volume contributions to the optical model potential. These relations are now utilized to obtain J/sub V/(A,E/sub p/) = J/sub V/(A,0)f(E/sub p/) and its imaginary counterpart, J/sub W//sub >//sub v//sub =/(A,E/sub p/) = J/sub V/(A,0)(1 -f(E/sub p/))/3. The results compare favorably with heuristic data and the findings of other approaches.

Amplitude analysis for hypercharge exchange reactions

The s channel helicity non-flip amplitudes for the line reversed reactions π N → K [ Σ, Λ] and KN → π [Σ, Λ] are determined directly from cross-section and polarization data at 4 GeV/ c. Rigorous bounds are obtained on the magnetudes of the flip amplitudes, whose phases are assumed to be given by an exchange degenerate K ∗ - K ∗∗ Regge trajectory. Our solution for the non-flip amplitude is unique and shows the following characteristics: i) Im K ∗ (Δλ = 0) has a “cross-over” zero at t ≈ −0.15 in both Σ and Λ reactions, ii) Im K ∗∗ (Δλ = 0) has an approximate double zero near t ≈ −0.6 in Σ reactions and a positive minimum there in Λ reactions, iii) Re K ∗ (Δλ = 0) and Re K ∗∗ (Δλ =0) are less peripheral in characters than their imaginary counter-part and have similar behavior at α = 0 to simple Regge poles.