scholarly journals Joint measurement of complementary observables in moment tomography

2017 ◽  
Vol 15 (08) ◽  
pp. 1740002
Author(s):  
Yong Siah Teo ◽  
Christian R. Müller ◽  
Hyunseok Jeong ◽  
Zdeněk Hradil ◽  
Jaroslav Řeháček ◽  
...  
Keyword(s):  
Quantum Information ◽  
General Theory ◽  
Single Mode ◽  
Continuous Variable ◽  
Quantum States ◽  
The Other ◽  
Joint Measurement ◽  
Other Hand ◽  
Sampling Procedures ◽  
Parameter Reconstruction

Wigner and Husimi quasi-distributions, owing to their functional regularity, give the two archetypal and equivalent representations of all observable-parameters in continuous-variable quantum information. Balanced homodyning (HOM) and heterodyning (HET) that correspond to their associated sampling procedures, on the other hand, fare very differently concerning their state or parameter reconstruction accuracies. We present a general theory of a now-known fact that HET can be tomographically more powerful than balanced homodyning to many interesting classes of single-mode quantum states, and discuss the treatment for two-mode sources.

scholarly journals Entangled resource for interfacing single- and dual-rail optical qubits

Quantum ◽  
2021 ◽  
Vol 5 ◽  
pp. 416
Author(s):  
David Drahi ◽  
Demid V. Sychev ◽  
Khurram K. Pirov ◽  
Ekaterina A. Sazhina ◽  
Valeriy A. Novikov ◽  
...  
Keyword(s):  
Quantum Information ◽  
Single Photon ◽  
Continuous Variable ◽  
Optical Field ◽  
The Other ◽  
Quantum Networks ◽  
Other Hand

Today's most widely used method of encoding quantum information in optical qubits is the dual-rail basis, often carried out through the polarisation of a single photon. On the other hand, many stationary carriers of quantum information – such as atoms – couple to light via the single-rail encoding in which the qubit is encoded in the number of photons. As such, interconversion between the two encodings is paramount in order to achieve cohesive quantum networks. In this paper, we demonstrate this by generating an entangled resource between the two encodings and using it to teleport a dual-rail qubit onto its single-rail counterpart. This work completes the set of tools necessary for the interconversion between the three primary encodings of the qubit in the optical field: single-rail, dual-rail and continuous-variable.

scholarly journals Deformation of finite morphisms and smoothing of ropes

2008 ◽  
Vol 144 (3) ◽  
pp. 673-688 ◽  
Author(s):  
Francisco Javier Gallego ◽  
Miguel González ◽  
Bangere P. Purnaprajna
Keyword(s):  
General Theory ◽  
Projective Space ◽  
General Result ◽  
The Other ◽  
Independent Interest ◽  
Higher Dimension ◽  
Smooth Curves ◽  
Other Hand ◽  
Finite Covers ◽  
The One

AbstractIn this paper we prove that most ropes of arbitrary multiplicity supported on smooth curves can be smoothed. By a rope being smoothable we mean that the rope is the flat limit of a family of smooth, irreducible curves. To construct a smoothing, we connect, on the one hand, deformations of a finite morphism to projective space and, on the other hand, morphisms from a rope to projective space. We also prove a general result of independent interest, namely that finite covers onto smooth irreducible curves embedded in projective space can be deformed to a family of 1:1 maps. We apply our general theory to prove the smoothing of ropes of multiplicity 3 on P1. Even though this paper focuses on ropes of dimension 1, our method yields a general approach to deal with the smoothing of ropes of higher dimension.

TELEPORTATION OF ANY FORM OF SINGLE-MODE QUANTUM STATES

2006 ◽  
Vol 20 (02n03) ◽  
pp. 97-103
Author(s):  
TONG-QIANG SONG
Keyword(s):  
Quantum Channel ◽  
Quantum Teleportation ◽  
Single Mode ◽  
Continuous Variable ◽  
Quantum States ◽  
Squeezed Vacuum ◽  
Einstein Podolsky Rosen ◽  
Epr Pair

By using the two-mode Einstein–Podolsky–Rosen (EPR) pair eigenstates or the two-mode squeezed vacuum as quantum channel we study the quantum teleportation of any form of single-mode quantum states (which include discrete and continuous variable quantum states). The elegant properties of the EPR pair eigenstates bring much convenience to our discussion.

scholarly journals From mimicry to mime by way of mimesis: Reflections on a general theory of iconicity

2010 ◽  
Vol 38 (1/4) ◽  
pp. 18-66 ◽  
Author(s):  
Göran Sonesson
Keyword(s):  
General Theory ◽  
Subject Matter ◽  
The Other ◽  
Other Hand ◽  
New Models ◽  
Iconic Sign ◽  
Iconic Signs ◽  
Animal World

Practically all theories of iconicity are denunciations of its subject matter (for example, those of Goodman, Bierman and the early Eco). My own theory of iconicity was developed in order to save a particular kind of iconicity, pictoriality, from such criticism. In this interest, I distinguished pure iconicity, iconic ground, and iconic sign, on one hand, and primary and secondary iconic signs, on the other hand. Since then, however, several things have happened. The conceptual tools that I created to explain pictoriality have been shown by others to be relevant to linguistic iconicity. On the other hand, semioticians with points of departure different from mine have identified mimicry as it is commonly found in the animal world as a species of iconicity. In the evolutionary semiotics of Deacon, iconicity is referred to in such a general way that it seems to be emptied of all content, while in the variety invented by Donald the term mimesis is used for a particular phase in the evolution of iconic meaning. The aim of this article is to consider to what extent the extension of iconicity theory to new domains will necessitate the development of new models.

scholarly journals Lernen und Problemlösen: Deweys Psychologie im bildungshistorischen Kontext

2016 ◽  
Vol 3 (2) ◽  
pp. 253
Author(s):  
Jürgen Oelkers
Keyword(s):  
Problem Solving ◽  
General Theory ◽  
The Other ◽  
Karl Popper ◽  
Project Method ◽  
Other Hand ◽  
History Of ◽  
Nature Studies ◽  
The One

Karl Popper called one of his latest collections of essays All Life is Problem Solving. Little is known about the history of «problem solving» and also Popper did not say much about his references. But his model of four stages of problem solving is clearly anticipated in John Dewey’s psychology of thinking. On the other hand Dewey’s How we Think (1910) cannot be understood without taken into account the contemporary movement in didactics. The article discusses two of them, «nature studies» on the one hand and the «project method» on the other. «Nature studies» is considered to be the counterpoint to problem-solving. William Kilpatrick’s project method is still closely linked with Dewey’s psychology but both concepts have to be studied independently. Dewey’s theory of problem-solving is a general theory of learning that cannot be reduced to didactics. But that reduction might explain why Popper did not pay attention to it.

History and the Businessman

1956 ◽  
Vol 30 (3) ◽  
pp. 241-259 ◽  
Author(s):  
W. Woodruf
Keyword(s):  
United States ◽  
Twentieth Century ◽  
General Theory ◽  
The United States ◽  
Human Experience ◽  
The Other ◽  
Focused Attention ◽  
Modern Times ◽  
Other Hand ◽  
Robber Baron

The distinguishing aspect of business in modern times, particularly in the United States, is that it has permeated the entire fabric of civilization. Historical interpretations of this circumstance have been in sharp conflict and have tended toward extremes. The wave of national self-criticism of the early twentieth century focused attention on the shortcomings of business, ignoring its constructive aspects. On the other hand, the modern revisionist school of historians, depicting the businessman not as a “robber baron” but as an “architect of material greatness,” has been prone to stress ends ahead of means and to overlook the deeper implications of the businessman's role in society as a whole. True perspective is not afforded by either of these opposing academic positions, nor is it likely to be gained by further blind amassing of facts-in-isolation on the part of business historians. A general theory of business evolution is needed — one that neither praises nor blames the businessman but seeks to locate him in the larger context of human experience.

scholarly journals On Feller’s Kernel and the Drichlet Norm

1964 ◽  
Vol 24 ◽  
pp. 167-175 ◽  
Author(s):  
Masatoshi Fukushima
Keyword(s):  
General Theory ◽  
Markov Processes ◽  
Green Space ◽  
The Other ◽  
Boundary Values ◽  
Dirichlet Integral ◽  
Additive Functionals ◽  
Other Hand ◽  
Dirichlet Norm

Recently J. L. Doob [2] evaluated the Dirichlet integral of the BLD harmonic funtion on a Green space in terms of its fine boundary values and θ-kernel of L. Naïm.On the other hand, the general theory of additive functionals of Markov processes enables us to define the concept of the Dirichlet norm of functions with respect to Markov processes.

scholarly journals NUMERICAL STUDY OF π-JUNCTION USING SPIN FILTERING BARRIERS

2009 ◽  
Vol 23 (20n21) ◽  
pp. 4320-4328 ◽  
Author(s):  
SHIRO KAWABATA ◽  
YASUHIRO ASANO
Keyword(s):  
Quantum Information ◽  
Band Structure ◽  
Josephson Junctions ◽  
Function Method ◽  
Numerical Study ◽  
Josephson Current ◽  
The Other ◽  
Other Hand ◽  
Spin Polarized ◽  
The Eu

We numerically investigate the Josephson transport through ferromagnetic insulators (FIs) by taking into account its band structure. By use of the recursive Green's function method, we found the formation of the π junction in the case of the fully spin-polarized FI (FPFI), e.g., La 2 BaCuO 5. Moreover, the 0-π transition is induced by increasing the thickness of FPFI. On the other hand, Josephson current through the Eu chalcogenides shows the π junction behavior in the case of the strong d-f hybridization between the conduction d and the localized f electrons of Eu . Such FI-based Josephson junctions may becomes a element in the architecture of future quantum information devices.

scholarly journals A squeezed quantum microcomb on a chip

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Zijiao Yang ◽  
Mandana Jahanbozorgi ◽  
Dongin Jeong ◽  
Shuman Sun ◽  
Olivier Pfister ◽  
...  
Keyword(s):  
Quantum Computing ◽  
Quantum Information ◽  
High Resolution ◽  
Quantum Information Processing ◽  
Frequency Comb ◽  
Continuous Variable ◽  
Quantum States ◽  
High Resolution Spectroscopy ◽  
Quantum Metrology ◽  
Universal Quantum

AbstractThe optical microresonator-based frequency comb (microcomb) provides a versatile platform for nonlinear physics studies and has wide applications ranging from metrology to spectroscopy. The deterministic quantum regime is an unexplored aspect of microcombs, in which unconditional entanglements among hundreds of equidistant frequency modes can serve as critical ingredients to scalable universal quantum computing and quantum networking. Here, we demonstrate a deterministic quantum microcomb in a silica microresonator on a silicon chip. 40 continuous-variable quantum modes, in the form of 20 simultaneously two-mode squeezed comb pairs, are observed within 1 THz optical span at telecommunication wavelengths. A maximum raw squeezing of 1.6 dB is attained. A high-resolution spectroscopy measurement is developed to characterize the frequency equidistance of quantum microcombs. Our demonstration offers the possibility to leverage deterministically generated, frequency multiplexed quantum states and integrated photonics to open up new avenues in fields of spectroscopy, quantum metrology, and scalable, continuous-variable-based quantum information processing.

Optimal class-specific witnesses for three-qubit entanglement from Greenberger-Horne-Zeilinger symmetry

2013 ◽  
Vol 13 (3&4) ◽  
pp. 210-220
Author(s):  
Christopher Eltschka ◽  
Jens Siewert
Keyword(s):  
Ghz State ◽  
Quantum States ◽  
Point Of View ◽  
The Other ◽  
Mixed States ◽  
Other Hand ◽  
New Type ◽  
The One ◽  
Qubit States ◽  
Symmetric States

Recently, a new type of symmetry for three-qubit quantum states was introduced, the so-called Greenberger-Horne-Zeilinger (GHZ) symmetry. It includes the operations which leave the three-qubit standard GHZ state unchanged. This symmetry is powerful as it yields families of mixed states that are, on the one hand, complex enough from the physics point of view and, on the other hand, simple enough mathematically so that their properties can be characterized analytically. We show that by using the properties of GHZ-symmetric states it is straightforward to derive optimal witnesses for detecting class-specific entanglement in arbitrary three-qubit states.

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