scholarly journals The role of localizable concurrence in quantum teleportation protocols

2021 ◽  
Vol 19 (05) ◽  
Author(s):  
Mirko Consiglio ◽  
Louis Zammit Mangion ◽  
Tony John George Apollaro

Teleporting an unknown qubit state is a paradigmatic quantum information processing task revealing the advantage of quantum communication protocols over their classical counterpart. For a teleportation protocol using a Bell state as quantum channel, the resource has been identified to be the concurrence. However, for mixed multipartite states the lack of computable entanglement measures has made the identification of the quantum resource responsible for this advantage more challenging. Here, by building on previous results showing that localizable concurrence is the necessary resource for controlled quantum teleportation, we show that any teleportation protocol using an arbitrary multipartite state, that includes a Bell measurement, requires a nonvanishing localizable concurrence between two of its parties to perform better than the classical protocol. By first analyzing Greenberger–Horne–Zeilinger (GHZ) channel and GHZ measurement teleportation protocol, in the presence of GHZ-symmetric-preserving noise, we compare different multipartite entanglement measures with the fidelity of teleportation, and we find that the protocol performs better than the classical protocol when all multipartite entanglement measures vanish, except for the localizable concurrence. Finally, we extend our proof to an arbitrary teleportation protocol with an arbitrary multipartite entangled channel.

Author(s):  
Konstantin Antipin

Abstract Genuine entanglement is the strongest form of multipartite entanglement. Genuinely entangled pure states contain entanglement in every bipartition and as such can be regarded as a valuable resource in the protocols of quantum information processing. A recent direction of research is the construction of genuinely entangled subspaces — the class of subspaces consisting entirely of genuinely entangled pure states. In this paper we present methods of construction of such subspaces including those of maximal possible dimension. The approach is based on the composition of bipartite entangled subspaces and quantum channels of certain types. The examples include maximal subspaces for systems of three qubits, four qubits, three qutrits. We also provide lower bounds on two entanglement measures for mixed states, the concurrence and the convex-roof extended negativity, which are directly connected with the projection on genuinely entangled subspaces.


Author(s):  
Mrittunjoy Guha Majumdar

Multipartite entanglement is a resource for application in disparate protocols, of computing, communication and cryptography. Nested entanglement provides resource-states for quantum information processing. In this paper, Matryoshka quantum resource-states, which contain nested entanglement patterns, has been studied. A novel scheme for the generation of such quantum states has been proposed using an anisotropic XY spin-spin interaction-based model. The application of the Matryoshka GHZ-Bell states for n-qubit teleportation is reviewed and an extension to more general Matryoshka ExhS-Bell states is posited. An example of Matryoshka ExhS-Bell states is given in the form of the genuinely entangled seven-qubit Xin-Wei Zha state. Generation, characterisation and application of this seven-qubit resource state in theoretical schemes for quantum teleportation of arbitrary one, two and three qubits states, bidirectional teleportation of arbitrary two qubit states and probabilistic circular controlled teleportation are presented.


2021 ◽  
Author(s):  
Hui Zhang ◽  
Lingxiao Wan ◽  
Tobias Haug ◽  
Wai-Keong Mok ◽  
Hong Cai ◽  
...  

Abstract Quantum teleportation transfers unknown quantum states from one node in a quantum network to another. It is one of the crucial architectures in quantum information processing. The teleportation of high-dimensional quantum states remains challenging due to the difficulties in executing high-dimensional Bell state measurement. Here, we propose a Quantum Autoencoder-Facilitated Teleportation (QAFT) protocol for high-dimensional quantum teleportation, and report the first demonstration of QAFT on qutrits using an integrated photonic platform for future scalability. The key strategy is to reduce the dimension of the input states by erasing redundant information and reconstruct its initial state after chip-to-chip teleportation. Machine learning is applied in training the autoencoder to facilitate the teleportation of any state from a particular high-dimensional subspace and achieve the reconstruction of the unknown state (by the decoder) with high fidelities (~ 0.971). Experimentally, we teleport unknown qutrits by generating, transferring and manipulating photons, and training quantum autoencoders on a silicon chip. A teleportation fidelity of ~ 0.894 is demonstrated. Our scheme opens pathway towards quantum internet and cryptography to transfer unmeasured states in a quantum computer. It also lays the groundwork for machine learning technologies in quantum networks and quantum computations.


Photonics ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 552
Author(s):  
Jianming Wen ◽  
Irina Novikova ◽  
Chen Qian ◽  
Chuanwei Zhang ◽  
Shengwang Du

By coherently combining advantages while largely avoiding limitations of two mainstream platforms, optical hybrid entanglement involving both discrete and continuous variables has recently garnered widespread attention and emerged as a promising idea for building heterogenous quantum networks. In contrast to previous results, here we propose a new scheme to remotely generate hybrid entanglement between discrete polarization and continuous quadrature optical qubits heralded by two-photon Bell-state measurement. As a novel nonclassical light resource, we further use it to discuss two examples of ways—entanglement swapping and quantum teleportation—in which quantum information processing and communications could make use of this hybrid technique.


Quantum ◽  
2017 ◽  
Vol 1 ◽  
pp. 35 ◽  
Author(s):  
Martin Ringbauer ◽  
Rafael Chaves

Correlations between spacelike separated measurements on entangled quantum systems are stronger than any classical correlations and are at the heart of numerous quantum technologies. In practice, however, spacelike separation is often not guaranteed and we typically face situations where measurements have an underlying time order. Here we aim to provide a fair comparison of classical and quantum models of temporal correlations on a single particle, as well as timelike-separated correlations on multiple particles. We use a causal modeling approach to show, in theory and experiment, that quantum correlations outperform their classical counterpart when allowed equal, but limited communication resources. This provides a clearer picture of the role of quantum correlations in timelike separated scenarios, which play an important role in foundational and practical aspects of quantum information processing.


2020 ◽  
Vol 51 (3) ◽  
pp. 795-806 ◽  
Author(s):  
Elizabeth J. Short ◽  
Rachael Cooper Schindler ◽  
Rita Obeid ◽  
Maia M. Noeder ◽  
Laura E. Hlavaty ◽  
...  

Purpose Play is a critical aspect of children's development, and researchers have long argued that symbolic deficits in play may be diagnostic of developmental disabilities. This study examined whether deficits in play emerge as a function of developmental disabilities and whether our perceptions of play are colored by differences in language and behavioral presentations. Method Ninety-three children participated in this study (typically developing [TD]; n = 23, developmental language disorders [DLD]; n = 24, attention-deficit/hyperactivity disorder [ADHD]; n = 26, and autism spectrum disorder [ASD]; n = 20). Children were videotaped engaging in free-play. Children's symbolic play (imagination, organization, elaboration, and comfort) was scored under conditions of both audible language and no audible language to assess diagnostic group differences in play and whether audible language impacted raters' perception of play. Results Significant differences in play were evident across diagnostic groups. The presence of language did not alter play ratings for the TD group, but differences were found among the other diagnostic groups. When language was audible, children with DLD and ASD (but not ADHD) were scored poorly on play compared to their TD peers. When language was not audible, children with DLD were perceived to play better than when language was audible. Conversely, children with ADHD showed organizational deficits when language was not available to support their play. Finally, children with ASD demonstrated poor play performance regardless of whether language was audible or not. Conclusions Language affects our understanding of play skills in some young children. Parents, researchers, and clinicians must be careful not to underestimate or overestimate play based on language presentation. Differential skills in language have the potential to unduly influence our perceptions of play for children with developmental disabilities.


2019 ◽  
Vol 2 (2) ◽  
pp. 1-7
Author(s):  
Andi Samsu Rijal ◽  
Andi Mega Januarti Putri

The essence of language is human activity. Communication with language is carried out through two basic human activities; speaking and listening during the interaction in a group of people. Immigrants in Makassar city communicate with immigrant communities and Makassar people. They used English and Indonesia to communicate with others. The aims of this article were to find out determinant factors of English as language choice among Unaccompanied Migrant Children (UMC) in Makassar and why they used English as their language choice to communicate with other people out of them. The data were taken from UMC in the shelter under the auspices of Makassar’s Social Office and in the public area of Makassar. This research was a qualitative approach; it was from a sociolinguistic perspective and focuses its analysis with the language choice among UMC. This research showed that most immigrants chose English as their language choice since they were in Makassar because they have acquired better than other international language and it has been mastered naturally by doing social interaction among themselves and people outside their community. UMC had more difficulties to socialize with Indonesian than the adult of Immigrants. Other than their lack of language mastery, they also have the anxiety to adapt to other immigrants and Makassar people. English was used by UMC to show their status as a foreigner who lived in a multicultural situation. Language becomes a power for a human being and it becomes a social identity for language user in one community. During the interaction of UMC in Makassar city, the role of English as an International language is shown.


2019 ◽  
pp. 58-62
Author(s):  
Vlad Stegariu ◽  
Simona Andreea Popușoi ◽  
Beatrice Abălașei ◽  
Nicolae Lucian Voinea ◽  
Ioan Stelescu ◽  
...  

Chess playing has a significant role in participants’ resources allocation, both at a psychological level, but mostly concerning the cognitive resources. The aim of the present study was to examine the effect of chess playing on the intellectual development of primary-class students. 67 children were tested using the Raven Standard Progressive Matrices and were distributed in three different groups according to their experience with chess, namely: the control group (formed by students with no experience with chess playing), the beginners group (students with less than one year in chess playing training) and the advanced group (children with more than two years experience with chess). Results indicated that chess playing had a significant effect on the SPM performance, indicating that those in the advanced group performed significantly better than those in the control or in the beginners group. Conclusions of this study tap into the benefits of playing chess with a focus on the children’s’ cognitive development.


Religions ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 206
Author(s):  
Pål Ketil Botvar

The Norwegian National Day (17 May, also referred to as Constitution Day) stands out as one of the most popular National Day celebrations in Europe. According to surveys, around seven out of every 10 Norwegians take part in a public celebration during this day. This means that the National Day potentially has an impact on the way people reflect upon national identity and its relationship to the Lutheran heritage. In this paper, I will focus on the role religion plays in the Norwegian National Day rituals. Researchers have described these rituals as both containing a significant religious element and being rather secularized. In this article, I discuss the extent to which the theoretical concepts civil religion and religious nationalism can help us understand the role of religion, or the absence of religion, in these rituals. Based on surveys of the general population, I analyze both indicators of civil religion and religious nationalism. The two phenomena are compared by looking at their relation to such items as patriotism, chauvinism, and xenophobia. The results show that civil religion explains participation in the National Day rituals better than religious nationalism.


Proceedings ◽  
2021 ◽  
Vol 77 (1) ◽  
pp. 15
Author(s):  
Hernan Mondani ◽  
Amir Rostami ◽  
Tina Askanius ◽  
Jerzy Sarnecki ◽  
Christofer Edling

This presentation summarizes a register-based study on women who have been identified as belonging to three violent extremist milieus in Sweden: violent Islamic, violent far-right, and violent far-left extremism. We studied the women in these milieus along a number of analytical dimensions, ranging from demographic and educational to criminal background and network relationships, and compared them to three reference groups: (i) non-extremist biological sisters to female extremists in the study population; (ii) men in the respective extremist milieus; and (iii) female members of other antagonistic milieus such as organized crime. Our results showed that there are both similarities and differences between groups. In some cases, like age and region of birth, there are commonalities between violent far-right and violent far-left women. Regarding region of birth and migration background, women affiliated to violent far-right and violent far-left extremism are predominantly born in Sweden. Women affiliated to violent Islamic extremism tend to be born in Sweden to a greater extent than men in the same milieu, but to a much lesser degree than women in the violent far-right and violent far-left. When it comes to education, women in the violent Islamic milieu are closer to women in violent far-right extremism. Women in violent far-left extremism perform best at school, with consistently higher grades. The average score of women in violent far-left extremism is identical to that of their sisters, and women in violent far-left extremism perform on average substantially better than men in the same milieu. Women in violent Islamic extremism, in contrast, perform on average similarly to men in violent far-left extremism, and they perform better than their biological sisters. Regarding labor market attachment, violent Islamic extremists have the weakest attachment and the highest dependency upon financial assistance as well as a low employment share (36 percent in 2016), but also a relatively high share of individuals with a high number of unemployment days, suggesting that women in violent Islamic extremism experience higher social exclusion. We find the highest employment share among women in violent far-left extremism, where 89 percent are gainfully employed in 2016 (80 percent for at least three of the last five years) and about a 20 percent unemployment share. Men in violent far-left extremism have an employment share around 10 percent below that of the women in far-left extremism for 2016. The highest fractions of individuals that have not been in contact with the health system due to mental disorders are among violent Islamic extremism, with the women’s fraction at 84 percent, compared to their non-extremist sisters and men in the same milieu that are just above 79 percent. Women in violent far-left extremism have the highest share of in-patient major mental disorders among the extremist milieus (3 percent), higher than men in the same milieu (less than 1 percent) as well as than women and their sisters in the other categories. During the period 2007–2016, 68 percent of individuals in the extremist milieus are covered by the register of suspected individuals. The coverage is substantially higher for men, 72 percent than for women, 43 percent. Compared to their sisters, women in all three milieus are criminally active to a much higher extent. However, women in all three milieus are less criminally active than women in other antagonistic milieus, among whom 67 percent have been suspected at least once. In all three milieus, the share of men with a criminal record is about twice as large as that of women. As far as the gender aspect is concerned, we know that extremist milieus generally have a conservative view of the role of women in society. In our results, this is reflected in the low rates of crime in women compared to men, and relatively marginal positions in the co-offending networks. The fact that women in violent far-left extremism have stronger positions in their networks than the other women in the study population is expected, given that the ideology of this milieu allows for greater equality. This means that women in violent far-left extremism participate more often than, e.g., women in violent far-right extremism, in political actions where violence is common. This pattern of gender roles and criminal involvement also holds concerning women in violent Islamic extremism. This milieu has a more traditional view of the role of women than views among even violent far-right extremists. Women in violent Islamic extremism are less involved in crime and, in particular, violent crime.


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