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S. B. Korolev

Publications and source records attributed to S. B. Korolev.

18 recordsLinked to original sources
arXiv2026

Generation of multicomponent Schrödinger cat states in schemes with measurement of Gaussian states

In this work, we propose a scheme for generating superpositions of Fock states whose numbers differ by four or eight. The proposed protocol is based on photon-number-resolving measurements on multimode Gaussian states. We compare of the generated states with multicomponent Schrödinger cat states. We evaluate the fidelity and determine how it scales with the number of detected particles. Furthermore, we derive the optimal configuration for the generation such states.

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arXiv2026

Growth of Schrödinger cats in particle-number measurement schemes

In this work, we investigate the generation of squeezed Schrödinger cat states in schemes based on photon-number-resolving measurements on multimode Gaussian states. We derive analytical expressions for the states generated in two- and three-mode schemes, as well as formulas for their fidelity with squeezed Schrödinger cat states. We analyze how the amplitude of the generated states scales with the number of detected particles. Furthermore, we derive an upper bound on the achievable generation fidelity and identify the conditions under which multimode schemes can enhance the quality of the generated states.

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arXiv2025

Generation of Squeezed Fock States by Particle-Number Measurements on Multimode Gaussian States

We investigate the generation of squeezed Fock states (SFSs) via particle-number measurements in the modes of multimode Gaussian states. We identify a universal class of $N$-mode Gaussian states for which measuring $N-1$ modes results in the generation of SFSs. The key feature of these states is that the generated SFSs depend only on the total number of detected particles and are independent of their distribution among the detectors. Based on the general form of the wave functions of multimode Gaussian states, we propose a universal scheme for SFS generation. For this scheme, we evaluate the probability of SFS generation and analyze the robustness of the process against imperfections in particle-number-resolving detectors. In addition, we compare the universal scheme with a nonuniversal scheme, in which the generation of SFSs depends on a specific distribution of particle numbers across the detectors. We demonstrate that the universal scheme provides a higher probability of SFS generation, at the cost of increased experimental resources.

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arXiv2025

Bosonic quantum error correction using squeezed Fock states

In the paper, we develop a bosonic quantum error correction code based on squeezed Fock states. We compare our proposed code with one based on squeezed Schrodinger's cat states using the Knill-Laflamme cost function and the Petz map fidelity. We demonstrate that squeezed Fock states are competitive in protecting information in a channel with particle loss and dephasing.

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arXiv2025

Tridirectional quantum teleportation protocol in continuous variables

We propose a protocol for tridirectional quantum teleportation in continuous variables. A special feature of the protocol is the possibility to choose one of three scenarios: simultaneous exchange between three participants, exchange between any two participants, or the transfer of two states to a third participant. We use a cluster state in continuous variables as the main resource to realise tridirectional quantum teleportation. In the paper, we obtain several possible configurations of cluster states in continuous variables that can be used as the main resource. From the whole range of configurations, we have chosen those that realise the protocol with the smallest possible error.

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arXiv2024

Comparison of Controlled-Z operation and beam-splitter transformation for generation of squeezed Fock states by measurement

The generation of squeezed Fock states by the one or more photon subtraction from a two-mode entangled Gaussian state using a beam splitter and a controlled-Z operation is addressed. From two different perspectives, we analyzed two entanglement transformations in the protocol. We evaluated the energy costs and resource requirements of the analyzed schemes. Furthermore, we studied the impact of experimental imperfections on the non-Gaussian states generated by measuring the number of particles. We explored the effects of photon loss and imperfect detectors on the squeezed Fock state generation protocol.

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arXiv2024

Bidirectional quantum teleportation in continuous variables

We propose a bidirectional quantum teleportation protocol in continuous variables. We use a cluster state in continuous variables as the main resource to realize this protocol. In the paper, we obtain a family of configurations of cluster states in continuous variables that can be used to realize the bidirectional quantum teleportation protocol. From the whole family of configurations, we have chosen those that realize the protocol with the smallest possible error.

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arXiv2024

Estimation of the set of states obtained in particle number measurement schemes

The paper investigated a set of non-Gaussian states generated by measuring the number of particles in one of the modes of a two-mode entangled Gaussian state. It was demonstrated that all generated states depend on two types of parameters: some parameters are responsible for Gaussian characteristics, while other parameters are responsible for non-Gaussian characteristics. Among all generated states, we identified those optimally generated in terms of the generation probability and the magnitude of non-Gaussianity.

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arXiv2024

Generation of squeezed Fock states by measurement

The generation of squeezed Fock states by the one or more photon subtraction from a two-mode entangled Gaussian (TMEG) state is theoretically addressed. We showed that an arbitrary order Fock state can be generated this way and we obtained a condition that should be imposed on the parameters of the TMEG state to guaranty such a generation. We called the regime, in which this condition is satisfied, universal solution regime. We showed that, for first squeezed Fock state, the above condition is redundant such that the generation of the first squeezed Fock state is still possible by a one photon subtraction from an arbitrary TMEG state. At the same time, the maximum generation probability of the first squeezed Fock state generation corresponds to the universal solution regime. We applied the above results to the description of generation of the squeezed Fock states using a beam splitter and a Controlled-Z operation. We have estimated the parameters of such setups and input squeezed states, which are necessary to obtain squeezed Fock states with the maximum probability.

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arXiv2023

Error Correction Using Squeezed Fock States

The paper addresses the construction an error correction code for quantum calculations based on squeezed Fock states. It is shown that the use of squeezed Fock states makes it possible to satisfy the Knill-Laflamme (KL) criteria for bosonic error correction codes. It is shown that the first squeezed Fock state corrects both photon loss and dephasing errors better than higher-order states. A comparison of the proposed protocol with an error correction protocol based on the squeezed Schrodinger's cat states is carried out on the basis of the KL cost function. It is shown that the squeezed first Fock state better protects a channel with photon loss and dephasing.

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arXiv2023

Generation of Non-Gaussian States in the Squeezed State Entanglement Scheme

The paper considers the possibility of generating different non-Gaussian states using the entangled state photon measurement scheme. In the paper, we have proposed a way to explicitly find the wave function and the Wigner function of the output state of this scheme. Moreover, the solutions found are not restricted to any particular case, but have maximum generality (depend on the number of measured photons and on all parameters of the scheme). Such a notation allowed us to carry out a complete analysis of the output states, depending on the scheme parameters. Using explicit expressions, we have analyzed the magnitude of non-Gaussianity of the output states, and we have revealed which particular states can be obtained in the proposed scheme. We have considered in detail a particular case of measurement (single photon measurement) and have shown that using explicit expressions for the output state wave function one can find scheme parameters to obtain states suitable for quantum error correction codes with a large fidelity value and high probability. The Schrodinger cat state with amplitude $α=2$ can be obtained with fidelity $F \approx 0.88$ and probability 18 percent, and the squeezed Schrodinger cat state ($α=0.5$, $R=1$) with fidelity $F \approx 0.98$ and probability 22 percent.

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arXiv2022

Error of an arbitrary single-mode Gaussian transformation on a weighted cluster state using a cubic phase gate

In this paper, we propose two strategies for decreasing the error of arbitrary single-mode Gaussian transformations implemented using one-way quantum computation on a four-node linear cluster state. We show that it is possible to minimize the error of the arbitrary single-mode Gaussian transformation by a proper choice of the weight coefficients of the cluster state. We modify the computation scheme by adding a non-Gaussian state obtained using a cubic phase gate as one of the nodes of the cluster. This further decreases the computation error. We evaluate the efficiencies of the proposed optimization schemes comparing the probabilities of the error correction of the quantum computations with and without optimizations. We have shown that for some transformations, the error probability can be reduced by up to 900 times.

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arXiv2022

Teleportation protocols with non-Gaussian operations: conditional photon subtraction versus cubic phase gate

In our work, we compare three teleportation protocols: the original protocol, the photon subtraction protocol, and the protocol with a cubic phase gate. We evaluate the fidelity of each protocol using the example of teleportation of the squeezed state and the Schrodinger's cat state. We show that, under equal conditions, the teleportation scheme with a cubic phase gate achieves significantly higher fidelity than the other protocols considered.

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arXiv2021

Teleportation with a cubic phase gate

We propose a modified quantum teleportation scheme to increase the teleportation accuracy by applying a cubic phase gate to the displaced squeezed state. We have described the proposed scheme in Heisenberg's language, evaluating it from the point of view of adding an error in teleportation, and have shown that it allows achieving less error than the original scheme. Repeating the description in the language of wave functions, we have found the range of the displacement values, at which our conclusions will be valid. Using the example of teleportation of the vacuum state, we have shown that the scheme allows one to achieve high fidelity values.

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arXiv2020

Finding the optimal cluster state configuration. Minimization of one-way quantum computation errors

In this paper, we estimate the errors of Gaussian transformations implemented using one-way quantum computations on cluster states of various configurations. From all possible cluster state configurations, we choose those that give the smallest computation error. Furthermore, we evaluate errors in hybrid computational schemes, in which Gaussian operations are performed using one-way computations with additional linear transformations. As a result, we find the optimal strategy for the implementation of universal Gaussian computations with minimal errors.

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arXiv2019

Criteria of minimum squeezing for quantum cluster state generation

In this paper, we assess possibilities of generating cluster states with different topologies being possessed of a finite squeezing resource of the initial oscillators used to generate a cluster state. We obtained the condition on minimum squeezing required for generating a cluster with a given topology as a simple estimation in terms of the coefficients of the adjacency matrix

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