Natalia Korolkova | University of St Andrews (original) (raw)
Papers by Natalia Korolkova
We demonstrate a general weak measurement model which allows Gaussian preserving entanglement con... more We demonstrate a general weak measurement model which allows Gaussian preserving entanglement concentration of the two mode squeezed vacuum. The power of this simple and elegant protocol is through the constraints it places on possible ancilla states and measurement strategies that will allow entanglement concentration. In particular, it is shown how previously discovered protocols of this kind emerge as special examples of the general model described here. Finally, as evidence of its utility, we use it to provide another novel example of such a protocol.
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In an initially uncorrelated mixed separable bi-partite system, quantum correlations can emerge u... more In an initially uncorrelated mixed separable bi-partite system, quantum correlations can emerge under the action of a local measurement or local noise [A. Streltsov, H. Kampermann, and D. Bruß, Phys. Rev. Lett. 107, 170502 (2011)]. We analyze this counter-intuitive phenomenon using quantum discord as a quantifier. We then relate changes in quantum discord to system-environment correlations between the system in a mixed state and some purifying environmental mode using the Koashi-Winter inequality. On this basis, we suggest an interpretation of discord as a byproduct of transferring entanglement and correlations around the different subsystems of a global pure state.
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We suggest and discuss a concept of deterministic integrated source of non-classical light based ... more We suggest and discuss a concept of deterministic integrated source of non-classical light based on the coherent diffusive photonics, a coherent light flow in a system of dissipatively coupled waveguides. We show how this practical quantum device can be realized with a system of single-mode waveguides laser-inscribed in nonlinear glass. We describe a hierarchy of models, from the complete multi-mode model of the waveguide network to the single mode coupled to a bath, analyze the conditions for validity of the simplest single-mode model and demonstrate feasibility of the generation of bright sub-Poissonian light states merely from a coherent input. Notably, the generation of non-classical states occurs at the initial stages of the dynamics, and can be accounted for in the linear model that allows us to circumvent the prohibiting computational complexity of the exact full quantum representation.
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Přednaska se týkala výzkumu ve třech oblastech, který probihal ve skupině kvantove optiky na univ... more Přednaska se týkala výzkumu ve třech oblastech, který probihal ve skupině kvantove optiky na univerzitě v St Andrews ve Skotsku: (1) Generovani negaussovských stavů pomoci tzv. Kerrovy nelinearity, (2) koncentrace kvantove provazanosti pomoci slabých měřeni a (3) distribuce provazanosti pomoci separabilniho stavu.
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Summary form only given. We report on a scheme for the generation of bright entangled light beams... more Summary form only given. We report on a scheme for the generation of bright entangled light beams aimed at quantum communication applications. The experiment is based on the recently proposed theme where two intense independently squeezed light fields interfere to produce multi-photon entangled light fields. An asymmetric fibre Sagnac interferometer is used.
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Frontiers in Optics, 2003
1. Summary The non-linear interaction between light pulses and matter depends on the amplitude an... more 1. Summary The non-linear interaction between light pulses and matter depends on the amplitude and phase distribution within the pulse. At equilibrium the non-linear dynamics of optical pulses in fibers produces solitons which are stable in a classical regime. In contrast, the quantum ...
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Physica Scripta, 2013
ABSTRACT The reliability of free-space quantum communication is strongly affected by turbulence p... more ABSTRACT The reliability of free-space quantum communication is strongly affected by turbulence present in atmospheric channels. The signal is randomly distorted or gets lost due to the fluctuations of atmospheric refractive index. We consider quantum communication with coherent and squeezed states and derive the fidelities for quantum states transmitted through such a free-space channel. We show that the fidelity can be significantly enhanced by postselecting high transmission events at the expense of decreasing transmission bit rate. Next, we introduce the witness function that characterizes the reliability of the reconciliation procedure between the communicating parties. Based on this measure, we suggest the receiver strategy that further improves the reconciliation quality.
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Journal of Modern Optics, 1996
We consider polarization-squeezed (PS) light generation in anisotropic Kerr medium. The fluctuati... more We consider polarization-squeezed (PS) light generation in anisotropic Kerr medium. The fluctuations of the Stokes parameter either S2 or S3 are suppressed in PS light. We show the possibility to transform PS light into light with sub-Poissonian statistics by linear conversion (phase plate and analyser). The quantum properties of the second harmonic (SH) generated by frequency doubling of the PS light are investigated.
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Physical Review A, 2019
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Reports on Progress in Physics
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Nature communications, Dec 4, 2017
A photonic circuit is generally described as a structure in which light propagates by unitary exc... more A photonic circuit is generally described as a structure in which light propagates by unitary exchange and transfers reversibly between channels. In contrast, the term 'diffusive' is more akin to a chaotic propagation in scattering media, where light is driven out of coherence towards a thermal mixture. Based on the dynamics of open quantum systems, the combination of these two opposites can result in novel techniques for coherent light control. The crucial feature of these photonic structures is dissipative coupling between modes, via an interaction with a common reservoir. Here, we demonstrate experimentally that such systems can perform optical equalisation to smooth multimode light, or act as a distributor, guiding it into selected channels. Quantum thermodynamically, these systems can act as catalytic coherent reservoirs by performing perfect non-Landauer erasure. For lattice structures, localised stationary states can be supported in the continuum, similar to compacton...
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Physical Review Letters, 2016
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2Nd International Workshop on Squeezed States and Uncertainty Relations, Mar 1, 1993
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Eprint Arxiv 0711 1808, Nov 1, 2007
We derive a cross-Kerr type effective Hamiltonian for the four-level atom interacting with three ... more We derive a cross-Kerr type effective Hamiltonian for the four-level atom interacting with three electromagnetic fields in the N-configuration. When the atom has relaxed into the ground state a cross-Kerr nonlinearity arises between two weak probe fields. As a development on earlier work we show in general that the atom will also display a linear and self-Kerr response. However, if certain resonance conditions are satisfied then the linear and self-Kerr interactions will vanish. The electrical susceptibilities of the probe transitions are also explored and it is shown that a large, pure cross-Kerr nonlinearity can be generated with vanishing absorption of both probe fields.
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Physical Review a Atomic Molecular and Optical Physics, 2006
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AIP Conference Proceedings, 2009
Weak values and entanglement concentration. [AIP Conference Proceedings 1110, 9 (2009)]. David Me... more Weak values and entanglement concentration. [AIP Conference Proceedings 1110, 9 (2009)]. David Menzies, Natalia Korolkova. Abstract. Weak measurements are a special class of indirect measurements where the signal system ...
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Physical Review Letters, 2015
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m with a pulse width around 130 fs. The nonlinear Kerr effect dominates the propagation owing to ... more m with a pulse width around 130 fs. The nonlinear Kerr effect dominates the propagation owing to the high peak power of up to 3.5kW. A half wave plate aligns the linearly po- larized light coming from the laser at a 45 angle with respect to the two main axes of the fiber ensuring an equal energy distribution between them.
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We present schemes for the generation and evaluation of continuous variable entanglement of brigh... more We present schemes for the generation and evaluation of continuous variable entanglement of bright optical beams and give a brief overview of a variety of optical techniques and quantum communi- cation applications on this basis. A new entanglement-based quantum interferometry scheme with bright beams is suggested. The performance of the presented schemes is independent of the relative interference phase which
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We demonstrate a general weak measurement model which allows Gaussian preserving entanglement con... more We demonstrate a general weak measurement model which allows Gaussian preserving entanglement concentration of the two mode squeezed vacuum. The power of this simple and elegant protocol is through the constraints it places on possible ancilla states and measurement strategies that will allow entanglement concentration. In particular, it is shown how previously discovered protocols of this kind emerge as special examples of the general model described here. Finally, as evidence of its utility, we use it to provide another novel example of such a protocol.
Bookmarks Related papers MentionsView impact
In an initially uncorrelated mixed separable bi-partite system, quantum correlations can emerge u... more In an initially uncorrelated mixed separable bi-partite system, quantum correlations can emerge under the action of a local measurement or local noise [A. Streltsov, H. Kampermann, and D. Bruß, Phys. Rev. Lett. 107, 170502 (2011)]. We analyze this counter-intuitive phenomenon using quantum discord as a quantifier. We then relate changes in quantum discord to system-environment correlations between the system in a mixed state and some purifying environmental mode using the Koashi-Winter inequality. On this basis, we suggest an interpretation of discord as a byproduct of transferring entanglement and correlations around the different subsystems of a global pure state.
Bookmarks Related papers MentionsView impact
We suggest and discuss a concept of deterministic integrated source of non-classical light based ... more We suggest and discuss a concept of deterministic integrated source of non-classical light based on the coherent diffusive photonics, a coherent light flow in a system of dissipatively coupled waveguides. We show how this practical quantum device can be realized with a system of single-mode waveguides laser-inscribed in nonlinear glass. We describe a hierarchy of models, from the complete multi-mode model of the waveguide network to the single mode coupled to a bath, analyze the conditions for validity of the simplest single-mode model and demonstrate feasibility of the generation of bright sub-Poissonian light states merely from a coherent input. Notably, the generation of non-classical states occurs at the initial stages of the dynamics, and can be accounted for in the linear model that allows us to circumvent the prohibiting computational complexity of the exact full quantum representation.
Bookmarks Related papers MentionsView impact
Přednaska se týkala výzkumu ve třech oblastech, který probihal ve skupině kvantove optiky na univ... more Přednaska se týkala výzkumu ve třech oblastech, který probihal ve skupině kvantove optiky na univerzitě v St Andrews ve Skotsku: (1) Generovani negaussovských stavů pomoci tzv. Kerrovy nelinearity, (2) koncentrace kvantove provazanosti pomoci slabých měřeni a (3) distribuce provazanosti pomoci separabilniho stavu.
Bookmarks Related papers MentionsView impact
Summary form only given. We report on a scheme for the generation of bright entangled light beams... more Summary form only given. We report on a scheme for the generation of bright entangled light beams aimed at quantum communication applications. The experiment is based on the recently proposed theme where two intense independently squeezed light fields interfere to produce multi-photon entangled light fields. An asymmetric fibre Sagnac interferometer is used.
Bookmarks Related papers MentionsView impact
Frontiers in Optics, 2003
1. Summary The non-linear interaction between light pulses and matter depends on the amplitude an... more 1. Summary The non-linear interaction between light pulses and matter depends on the amplitude and phase distribution within the pulse. At equilibrium the non-linear dynamics of optical pulses in fibers produces solitons which are stable in a classical regime. In contrast, the quantum ...
Bookmarks Related papers MentionsView impact
Physica Scripta, 2013
ABSTRACT The reliability of free-space quantum communication is strongly affected by turbulence p... more ABSTRACT The reliability of free-space quantum communication is strongly affected by turbulence present in atmospheric channels. The signal is randomly distorted or gets lost due to the fluctuations of atmospheric refractive index. We consider quantum communication with coherent and squeezed states and derive the fidelities for quantum states transmitted through such a free-space channel. We show that the fidelity can be significantly enhanced by postselecting high transmission events at the expense of decreasing transmission bit rate. Next, we introduce the witness function that characterizes the reliability of the reconciliation procedure between the communicating parties. Based on this measure, we suggest the receiver strategy that further improves the reconciliation quality.
Bookmarks Related papers MentionsView impact
Journal of Modern Optics, 1996
We consider polarization-squeezed (PS) light generation in anisotropic Kerr medium. The fluctuati... more We consider polarization-squeezed (PS) light generation in anisotropic Kerr medium. The fluctuations of the Stokes parameter either S2 or S3 are suppressed in PS light. We show the possibility to transform PS light into light with sub-Poissonian statistics by linear conversion (phase plate and analyser). The quantum properties of the second harmonic (SH) generated by frequency doubling of the PS light are investigated.
Bookmarks Related papers MentionsView impact
Physical Review A, 2019
Bookmarks Related papers MentionsView impact
Reports on Progress in Physics
Bookmarks Related papers MentionsView impact
Nature communications, Dec 4, 2017
A photonic circuit is generally described as a structure in which light propagates by unitary exc... more A photonic circuit is generally described as a structure in which light propagates by unitary exchange and transfers reversibly between channels. In contrast, the term 'diffusive' is more akin to a chaotic propagation in scattering media, where light is driven out of coherence towards a thermal mixture. Based on the dynamics of open quantum systems, the combination of these two opposites can result in novel techniques for coherent light control. The crucial feature of these photonic structures is dissipative coupling between modes, via an interaction with a common reservoir. Here, we demonstrate experimentally that such systems can perform optical equalisation to smooth multimode light, or act as a distributor, guiding it into selected channels. Quantum thermodynamically, these systems can act as catalytic coherent reservoirs by performing perfect non-Landauer erasure. For lattice structures, localised stationary states can be supported in the continuum, similar to compacton...
Bookmarks Related papers MentionsView impact
Physical Review Letters, 2016
Bookmarks Related papers MentionsView impact
2Nd International Workshop on Squeezed States and Uncertainty Relations, Mar 1, 1993
Bookmarks Related papers MentionsView impact
Eprint Arxiv 0711 1808, Nov 1, 2007
We derive a cross-Kerr type effective Hamiltonian for the four-level atom interacting with three ... more We derive a cross-Kerr type effective Hamiltonian for the four-level atom interacting with three electromagnetic fields in the N-configuration. When the atom has relaxed into the ground state a cross-Kerr nonlinearity arises between two weak probe fields. As a development on earlier work we show in general that the atom will also display a linear and self-Kerr response. However, if certain resonance conditions are satisfied then the linear and self-Kerr interactions will vanish. The electrical susceptibilities of the probe transitions are also explored and it is shown that a large, pure cross-Kerr nonlinearity can be generated with vanishing absorption of both probe fields.
Bookmarks Related papers MentionsView impact
Physical Review a Atomic Molecular and Optical Physics, 2006
Bookmarks Related papers MentionsView impact
AIP Conference Proceedings, 2009
Weak values and entanglement concentration. [AIP Conference Proceedings 1110, 9 (2009)]. David Me... more Weak values and entanglement concentration. [AIP Conference Proceedings 1110, 9 (2009)]. David Menzies, Natalia Korolkova. Abstract. Weak measurements are a special class of indirect measurements where the signal system ...
Bookmarks Related papers MentionsView impact
Physical Review Letters, 2015
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
m with a pulse width around 130 fs. The nonlinear Kerr effect dominates the propagation owing to ... more m with a pulse width around 130 fs. The nonlinear Kerr effect dominates the propagation owing to the high peak power of up to 3.5kW. A half wave plate aligns the linearly po- larized light coming from the laser at a 45 angle with respect to the two main axes of the fiber ensuring an equal energy distribution between them.
Bookmarks Related papers MentionsView impact
We present schemes for the generation and evaluation of continuous variable entanglement of brigh... more We present schemes for the generation and evaluation of continuous variable entanglement of bright optical beams and give a brief overview of a variety of optical techniques and quantum communi- cation applications on this basis. A new entanglement-based quantum interferometry scheme with bright beams is suggested. The performance of the presented schemes is independent of the relative interference phase which
Bookmarks Related papers MentionsView impact