Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2010.14552 · Physical Review A

Gain in performance of teleportation with uniformity-breaking distributions

Saptarshi Roy, Shiladitya Mal, Aditi Sen

Published Feb 16, 2022• 5 citations
arXivHTMLPDF

Abstract

Prior information about an input state can be utilized to enhance the efficiency of quantum teleportation, which we quantify using the first two moments of fidelity. The input knowledge is introduced by relaxing the uniformity assumption in the distribution of the input state and considering nonuniform distributions, namely, the polar cap and von Mises--Fisher densities. For these distributions, we show that the average fidelity increases depending on the shared resource state between the sender and the receiver, while the deviation decreases with the increase of information content about the input ensemble, thereby establishing its role as a resource. Our comparative study between these two distributions reveals that for the same amount of information content about inputs, although the average fidelity yield is the same for both, the polar cap distribution is better as it offers a smaller deviation. Moreover, we contrast the resource of prior information with other resources involved in the protocol such as shared entanglement and classical communication. Specifically, we observe that unlike a uniform distribution, the amount of classical communication required to fulfill the task decreases with the increase of information available for inputs. We also investigate the role of prior information in higher- (three-)dimensional teleportation and report the characteristics of the dimensional advantage in prior information-based teleportation.

DOI
10.1103/physreva.105.022610

Related papers

Benchmark for Quantum Teleportation with Non-Uniform Prior Distributions

Tomáš Opatrný, Allison Brattley, Kunal K. Das

Quantum teleportation should surpass maximum fidelity thresholds possible with local measurements and classical communications. Benchmarks have been established when states are drawn from a uniform distribution of qubits or coherent states of harmonic oscillators. These are not applicable when there is prior knowledge about the input that skews the distribution. We determine the highest mean fidelity achievable for teleportation of states without using entanglement but drawn from a non-uniform prior distribution, specifically a von Mises - Fisher distribution. Using Bayesian methods, we derive benchmark functions for single qubit teleportation that utilize projective measurement on specific axes on the Bloch sphere. We demonstrate that similar results can be achieved with a coherent spin positive operator-valued measure (POVM), based upon heterodyne detection. These methods are then used to derive corresponding benchmarks for teleporting multi-qubit systems that we model as spin coherent states, covering the full range of particle number $N\in [1, \infty)$. The results show that fidelity thresholds to declare quantum advantage can be significantly higher than is typically assumed with uniform distribution.

quant-pharXiv:2605.24861•May 26, 2026•0 citations

Universality cost of non-Gaussian enhancement in continuous-variable quantum teleportation: A fidelity--deviation trade-off

Kyoungho Cho, Bongjune Kim, Jeongho Bang

Continuous-variable (CV) quantum teleportation is usually benchmarked by average fidelity, but when the teleportation is repeatedly used within optical networks or measurement-based architectures, uniformity across the input ensemble becomes equally important. We analyze this issue using two complementary figures of merit: the average fidelity and the fidelity deviation, which quantifies the input dependence of the single-shot teleportation fidelity. We prove that any deterministic unity-gain teleportation channel that is displacement covariant has vanishing fidelity deviation for coherent-state benchmarking, irrespective of whether the shared entangled resource is Gaussian or non-Gaussian. Nonzero deviation therefore diagnoses covariance breaking rather than non-Gaussianity. We then show that when a protocol raises the average fidelity through input-selective conditioning, the deviation generically increases in tandem, giving a quantitative universality cost. As a concrete example, we study teleportation enhanced by the so-called measurement-based noiseless linear amplification, where a heralded filter acts on the Bell-measurement record. The resulting trade-off among average fidelity, fidelity deviation, and success probability shows that stronger filtering can improve the conditional fidelity only by concentrating the successful events in favored regions of phase space, thereby suppressing the success probability and reducing input uniformity. Our results provide an operational framework for distinguishing genuine channel improvement from selectivity-driven post-selected advantage and suggest that the probabilistic CV teleportation should be assessed with average quality, universality, and heralding rate treated on an equal footing.

quant-pharXiv:2604.20103•Physical Review A•Apr 23, 2026•1 citation

Significance of fidelity deviation in continuous-variable teleportation

Ayan Patra, Rivu Gupta, Saptarshi Roy +1 more

Performance of quantum teleportation is typically measured by the average fidelity, an overlap between the input and output states. Along with the first moment, we introduce the second moment of fidelity in continuous-variable (CV) teleportation, i.e., the fidelity deviation as the figure of merit to assess the protocol's efficiency. We show that CV states, both Gaussian and non-Gaussian, can be better characterized by considering both average fidelity and fidelity deviation, which is not possible with only average fidelity. Moreover, we shed light on the performance of the teleportation protocol in two different input scenarios: One is when input states are sampled from constrained uniform distribution while the other one is Gaussian suppression of the input states which again leads to a different classification of CV states according to their performance. The entire analysis is carried out in noiseless and noisy scenarios with noise being incorporated in the measurement and the shared channels. We also report that one type of noise can make the protocol robust against the other one, which leads to a ``constructive effect,'' and identify the noise models which are responsible for decreasing average fidelity and the increment in fidelity deviation.

arXiv:2203.06684•Physical Review A•Aug 26, 2022•6 citations

Activation of entanglement in teleportation

Ryszard Weinar, Wiesław Laskowski, Marcin Pawłowski

We study the activation of entanglement in teleportation protocols. To this end, we a present derivation of the average fidelity of teleportation process with noisy classical channel for qudits. In our work we do not make any assumptions about the entangled states shared by communicating parties. Our result allows us to specify the minimum amount of classical information required to beat the classical limit when the protocol is based on the Bell measurements. We also compare average fidelity of teleportation obtained using noisy and perfect classical channel with restricted capacity. The most important insight into the intricacies of quantum information theory that we gain is that though entanglement, obviously, is a necessary resource for efficient teleportation it requires a certain threshold amount of classical communication to be more useful than classical communication. Another interesting finding is that the amount of classical communication required to activate entanglement for teleportation purposes depends on the dimension d of the system being teleported but is not monotonic reaching maximum for d = 4.

arXiv:1305.3443•Journal of Physics A Mathematical and Theoretical•Oct 8, 2013•5 citations

Witness wedges in fidelity-deviation plane: separating teleportation advantage and Bell-inequality violation

Kyoungho Cho, Jeongho Bang

We develop a unified framework to analyze $d$-dimensional quantum teleportation through the joint geometry of two complementary figures of merit: average fidelity $F$ (how well a protocol works on average) and fidelity deviation $D$ (how uniformly it works across the inputs). Technically, we formulate a representation-theoretical framework based on Schur-Weyl duality and permutation symmetry calculus that reduce the higher-moment Haar averages to a finite set of trace invariants of the composed correction unitaries. This yields closed-form expressions for $F$ and $D$ in arbitrary Hilbert-space dimension and delivers tight bounds that link the admissible deviation directly to the gap from the optimal average performance. In particular, any measured pair $(F, D)$ can be ported into a visibility estimate for isotropic channel resources, turning the $(F, D)$-plane into a calibrated diagnostic map. We further cast the teleportation advantage and CGLMP-inequality violation as two witnesses lines in the $(F,D)$ plane: one line certifies that $F$ beats the classical benchmark $2/(d{+}1)$, while the other line certifies the Bell nonlocality. Their identical slope but distinct intercepts expose a quantitative gap between "entangled yet local" and "genuinely nonlocal" resources.

quant-pharXiv:2511.21079•Physical Review A•Nov 27, 2025•0 citations

Rating the performance of noisy teleportation using fluctuations in fidelity

Saptarshi Roy, Arkaprabha Ghosal

Quantum teleportation is one of the most pioneering features of the quantum world. Typically, the quality of a teleportation protocol is solely judged by its average fidelity. In this work, we analyze the performance of teleportation in terms of both fidelity and the deviation in fidelity. Specifically, we define a quantity called teleportability score, which incorporates contributions from both the fidelity and its deviation. It also takes into account the sensitivity one requires for a protocol in which the teleportation of a quantum state is required in one or many intermediate steps. We compute the teleportability score in the noiseless scenario and find that it increases monotonically with the entanglement content of the considered pure resource states. The result remains the same even if we consider an $n$-chain repeater-like configuration. However, in the presence of noise, the teleportability score can sometime display a nonmonotonic behavior with respect to the entanglement content of the initially shared resource state. Specifically, under local bit-flip and bit-phase-flip noise, less entangled states can have higher teleportability score for certain choices of system parameters. In the presence of global depolarizing noise, for low entangled resource states and high sensitivity requirements, the noisy states can have better a teleportability score in comparison to the noiseless scenario.

arXiv:2001.11463•Physical Review A•Jul 30, 2020•7 citations
Prior information about an input state can be utilized to enhance the efficiency of quantum teleportation, which we quantify using the first two moments of fidelity. The input knowledge is introduced by relaxing the uniformity assumption in the distribution of the input state and considering nonuniform distributions, namely, the polar cap and von Mises--Fisher densities. For these distributions, we show that the average fidelity increases depending on the shared resource state between the sender and the receiver, while the deviation decreases with the increase of information content about the input ensemble, thereby establishing its role as a resource. Our comparative study between these two distributions reveals that for the same amount of information content about inputs, although the average fidelity yield is the same for both, the polar cap distribution is better as it offers a smaller deviation. Moreover, we contrast the resource of prior information with other resources involved in the protocol such as shared entanglement and classical communication. Specifically, we observe that unlike a uniform distribution, the amount of classical communication required to fulfill the task decreases with the increase of information available for inputs. We also investigate the role of prior information in higher- (three-)dimensional teleportation and report the characteristics of the dimensional advantage in prior information-based teleportation.
Quantum teleportation should surpass maximum fidelity thresholds possible with local measurements and classical communications. Benchmarks have been established when states are drawn from a uniform distribution of qubits or coherent states of harmonic oscillators. These are not applicable when there is prior knowledge about the input that skews the distribution. We determine the highest mean fidelity achievable for teleportation of states without using entanglement but drawn from a non-uniform prior distribution, specifically a von Mises - Fisher distribution. Using Bayesian methods, we derive benchmark functions for single qubit teleportation that utilize projective measurement on specific axes on the Bloch sphere. We demonstrate that similar results can be achieved with a coherent spin positive operator-valued measure (POVM), based upon heterodyne detection. These methods are then used to derive corresponding benchmarks for teleporting multi-qubit systems that we model as spin coherent states, covering the full range of particle number N∈[1,∞)N\in [1, \infty)N∈[1,∞). The results show that fidelity thresholds to declare quantum advantage can be significantly higher than is typically assumed with uniform distribution.
Continuous-variable (CV) quantum teleportation is usually benchmarked by average fidelity, but when the teleportation is repeatedly used within optical networks or measurement-based architectures, uniformity across the input ensemble becomes equally important. We analyze this issue using two complementary figures of merit: the average fidelity and the fidelity deviation, which quantifies the input dependence of the single-shot teleportation fidelity. We prove that any deterministic unity-gain teleportation channel that is displacement covariant has vanishing fidelity deviation for coherent-state benchmarking, irrespective of whether the shared entangled resource is Gaussian or non-Gaussian. Nonzero deviation therefore diagnoses covariance breaking rather than non-Gaussianity. We then show that when a protocol raises the average fidelity through input-selective conditioning, the deviation generically increases in tandem, giving a quantitative universality cost. As a concrete example, we study teleportation enhanced by the so-called measurement-based noiseless linear amplification, where a heralded filter acts on the Bell-measurement record. The resulting trade-off among average fidelity, fidelity deviation, and success probability shows that stronger filtering can improve the conditional fidelity only by concentrating the successful events in favored regions of phase space, thereby suppressing the success probability and reducing input uniformity. Our results provide an operational framework for distinguishing genuine channel improvement from selectivity-driven post-selected advantage and suggest that the probabilistic CV teleportation should be assessed with average quality, universality, and heralding rate treated on an equal footing.
Performance of quantum teleportation is typically measured by the average fidelity, an overlap between the input and output states. Along with the first moment, we introduce the second moment of fidelity in continuous-variable (CV) teleportation, i.e., the fidelity deviation as the figure of merit to assess the protocol's efficiency. We show that CV states, both Gaussian and non-Gaussian, can be better characterized by considering both average fidelity and fidelity deviation, which is not possible with only average fidelity. Moreover, we shed light on the performance of the teleportation protocol in two different input scenarios: One is when input states are sampled from constrained uniform distribution while the other one is Gaussian suppression of the input states which again leads to a different classification of CV states according to their performance. The entire analysis is carried out in noiseless and noisy scenarios with noise being incorporated in the measurement and the shared channels. We also report that one type of noise can make the protocol robust against the other one, which leads to a ``constructive effect,'' and identify the noise models which are responsible for decreasing average fidelity and the increment in fidelity deviation.
We study the activation of entanglement in teleportation protocols. To this end, we a present derivation of the average fidelity of teleportation process with noisy classical channel for qudits. In our work we do not make any assumptions about the entangled states shared by communicating parties. Our result allows us to specify the minimum amount of classical information required to beat the classical limit when the protocol is based on the Bell measurements. We also compare average fidelity of teleportation obtained using noisy and perfect classical channel with restricted capacity. The most important insight into the intricacies of quantum information theory that we gain is that though entanglement, obviously, is a necessary resource for efficient teleportation it requires a certain threshold amount of classical communication to be more useful than classical communication. Another interesting finding is that the amount of classical communication required to activate entanglement for teleportation purposes depends on the dimension d of the system being teleported but is not monotonic reaching maximum for d = 4.
We develop a unified framework to analyze ddd-dimensional quantum teleportation through the joint geometry of two complementary figures of merit: average fidelity FFF (how well a protocol works on average) and fidelity deviation DDD (how uniformly it works across the inputs). Technically, we formulate a representation-theoretical framework based on Schur-Weyl duality and permutation symmetry calculus that reduce the higher-moment Haar averages to a finite set of trace invariants of the composed correction unitaries. This yields closed-form expressions for FFF and DDD in arbitrary Hilbert-space dimension and delivers tight bounds that link the admissible deviation directly to the gap from the optimal average performance. In particular, any measured pair (F,D)(F, D)(F,D) can be ported into a visibility estimate for isotropic channel resources, turning the (F,D)(F, D)(F,D)-plane into a calibrated diagnostic map. We further cast the teleportation advantage and CGLMP-inequality violation as two witnesses lines in the (F,D)(F,D)(F,D) plane: one line certifies that FFF beats the classical benchmark 2/(d+1)2/(d{+}1)2/(d+1), while the other line certifies the Bell nonlocality. Their identical slope but distinct intercepts expose a quantitative gap between "entangled yet local" and "genuinely nonlocal" resources.
Quantum teleportation is one of the most pioneering features of the quantum world. Typically, the quality of a teleportation protocol is solely judged by its average fidelity. In this work, we analyze the performance of teleportation in terms of both fidelity and the deviation in fidelity. Specifically, we define a quantity called teleportability score, which incorporates contributions from both the fidelity and its deviation. It also takes into account the sensitivity one requires for a protocol in which the teleportation of a quantum state is required in one or many intermediate steps. We compute the teleportability score in the noiseless scenario and find that it increases monotonically with the entanglement content of the considered pure resource states. The result remains the same even if we consider an nnn-chain repeater-like configuration. However, in the presence of noise, the teleportability score can sometime display a nonmonotonic behavior with respect to the entanglement content of the initially shared resource state. Specifically, under local bit-flip and bit-phase-flip noise, less entangled states can have higher teleportability score for certain choices of system parameters. In the presence of global depolarizing noise, for low entangled resource states and high sensitivity requirements, the noisy states can have better a teleportability score in comparison to the noiseless scenario.