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Entanglement of high-dimensional multipartite systems plays an important role both in quantum foundation and applications of quantum physics. Inspired by the genuine high-dimensional entanglement (Kraft et al. in Phys Rev Lett 120:060502, 2018), we first propose a new criterion to characterize genuine entangled states in arbitrary finite dimensional systems. We further define two decomposable models by using embedding method for featuring experimentally untrusted parties. We show that the equivalence of local decomposability and embedded decomposability holds under special conditions for entangled pure states. For mixed states, we show the decomposability may be changed in embedded space. [ABSTRACT FROM AUTHOR]

The parameterized entanglement monotone, the q-concurrence, is also a reasonable parameterized entanglement measure. By exploring the properties of the q-concurrence with respect to the positive partial transposition and realignment of density matrices, we present tight lower bounds of the q-concurrence for arbitrary q ≥ 2 . Detailed examples are given to show that the bounds are better than the previous ones. [ABSTRACT FROM AUTHOR]

We investigate the preservation of quantum coherence and entanglement carried by the three non-interacting qubits during their evolution in the presence of an external fluctuating field characterized by a classical Gaussian noise. Initially, the three non-interacting qubits are considered in two different maximally entangled states, namely Greenberger–Horne–Zeilinger ( X G ) and Werner (X W) state. Besides this, we study the time evolution of the two states in three different schemes, namely: common, mixed, and independent system–environment couplings. By deploying different measures, we show that the system–environment coupling and the Gaussian noise greatly affected the quantum correlation and coherence. We also found that the non-local correlation and coherence remain more dominant and robust in common system–environment coupling for the X G state under the Gaussian noise. Hence, this kind of feature of the X G state is a vital resource for the transmission of quantum information with reduced loss. [ABSTRACT FROM AUTHOR]

The monogamy of quantum entanglement captures the property of limitation in the distribution of entanglement. Various monogamy relations exist for different entanglement measures that are important in quantum information processing. Our goal in this work is to propose general monogamy inequalities for several entanglement measures on entangled qubit systems. The present results provide a unified model for various entanglement measures including the concurrence, the negativity, the entanglement of formation, Tsallis-q entropy, Rényi-q entropy, and Unified-(q, s) entropy. We then propose tightened monogamy inequalities for multipartite qubit systems and derive upper bounds of aforementioned entanglement measures for multipartite pure state under generalized bipartitions. We finally prove a generic result that most of tripartite high-dimensional entangled pure states have no entanglement monogamy. These results are useful for exploring the entanglement theory, quantum information processing and secure quantum communication. [ABSTRACT FROM AUTHOR]

The main weakness of entanglement is its sensitiveness to the photon loss. In this paper, we exploit the different transmission losses of the free-space and optical fiber quantum channels, to develop a novel approach for (2,3) threshold quantum secret sharing (QSS) of classical information. To be exact, the Dealer Alice allocates W-state to three participants Bob, Charlie and David in terms of the asymmetric losses of their quantum channels, preventing any one participant from recovering the secret alone, but allowing any two of them to recover the secret. In such a way, Alice can flexibly choose the suitable degree of freedom to allocate the quantum shares with respect to the loss characteristics of different quantum channels. Our proposed scheme improves the information capacity from three bits to (log 2 m + 2) bits, where m denotes the dimension of orbital angular momentum, and improves the security and flexibility of quantum communication, confirming QSS as a realistic technology for safeguarding secret shares in transmission. This work opens a convenient and favorable way to perform QSS. [ABSTRACT FROM AUTHOR]

Multipartite entangled state plays a crucial role in quantum applications. We propose theoretical schemes to generate entanglements among several trapped atoms with the help of quantum dots in single-side optical microcavities. In the first scheme, a basic architecture will be built to produce arbitrary N-atom GHZ state by using only one auxiliary photon. Moreover, using a photon state with multiple modes, we can realize $$2^n$$ -atom W state. All these schemes are insensitive to the variation of the atom-photon coupling rates and are also right for remotely trapped atoms by using the photonic transmissions, local quantum operations, and classical channel. Simulations show that our schemes are faithful and available with present physical techniques. [ABSTRACT FROM AUTHOR]

The ability to prepare arbitrary quantum state is the holy grail of quantum information technology. Previous schemes focus on circuit complexity using implicit decomposition schemes for global evolutions and are difficult in quantum experiments because the generation circuit can be completed for given coefficients each time. One protocol is firstly proposed in this paper in order to deterministically generate arbitrary four-qubit states with any coefficients. In order to complete this scheme with present physical techniques, we present an explicit quantum circuit with unknown coefficients of prepared states using elementary quantum gates. The key of our scheme is constructing the Cartan KAK decomposition of special transformations in $$SO(4)$$ and $$SO(8)$$ . And then, this protocol is extended to arbitrary five-qubit states and six-qubit states. [ABSTRACT FROM AUTHOR]

Two schemes via different entangled resources as the quantum channel are proposed to realize remote preparation of an arbitrary four-particle $$\chi $$ -state with high success probabilities. To design these protocols, some useful and general measurement bases are constructed, which have no restrictions on the coefficients of the prepared states. It is shown that through a four-particle projective measurement and two-step three-particle projective measurement under the novel sets of mutually orthogonal basis vectors, the original state can be prepared with the probability 50 and 100 %, respectively. And for the first scheme, the special cases of the prepared state that the success probability reaches up to 100 % are discussed by the permutation group. Furthermore, the present schemes are extended to the non-maximally entangled quantum channel, and the classical communication costs are calculated. [ABSTRACT FROM AUTHOR]

In this work, novel schemes for joint remote state preparation are presented, which involve N senders and 2 receivers as well as N senders and 3 receivers. The receivers can simultaneously reconstruct different qubit states containing the joint information from all senders. Compared with the protocols proposed by Su et al. (Int J Quantum Inf 10:1250006 (), the information of the prepared states in our schemes is distributed in a different way. Our protocols can be applied not only to states with real parameters but also ones with complex parameters. Moreover, the N-to-2 protocol is suitable for general qubit states besides equatorial states, and the receivers need not to perform any measurements and CNOT gates to reconstruct the states. [ABSTRACT FROM AUTHOR]

The quantum no-cloning theorem and no-deleting theorem may be the most important quantum features for quantum communications or quantum computations. In this paper, we concentrate typical properties of random quantum evolution. We obtain that universal random evolutions change the generic unknown pure states into their orthogonal states approximately. Moreover, typical random evolutions distort the von Neumann entropy with constants. These results are extended to mixed states with a stronger orthogonal preparation ability. These typical characters are very important for quantum information retrieving or various quantum tasks. [ABSTRACT FROM AUTHOR]

This paper is to investigate the rational approximation of the unitary groups. Specially, based on the Household decomposition we prove that the rational unitary subgroup is dense in the complex unitary group. Moreover, its random approximate property is characterized by the natural Harr measure, which can be used to obtain random unitary matrix. Our simulation shows that these results may be applied to approximate quantum computations. [ABSTRACT FROM AUTHOR]

The protocols for joint remote preparation of an arbitrary two-particle pure state from a spatially separated multi-sender to one receiver are presented in this paper. We first consider the situation of two sender and demonstrate a flexible deterministic joint remote state preparation compared with previous probabilistic schemes. And then generalize the protocol to multi-sender and show that by only adding some classical communication the success probability of preparation can be increased to four times. Finally, using a proper positive operator-valued measure instead of usual projective measurement, we present a new scheme via two non-maximally entangled states. It is shown that our schemes are generalizations of the usual standard joint remote state preparation scheme and more suitable for real experiments with requirements of only Pauli operations. [ABSTRACT FROM AUTHOR]

The main superiority of the quantum remote preparation over quantum teleportation lies the classical resource saving. This situation may be changed from the following constructions. Our purpose in this paper is to find some special differences between these two quantum tasks besides the classical resource costs. Some novel schemes show that the first one is useful to simultaneously broadcast arbitrary quantum states, while the second one cannot because of the quantum no-cloning theorem. Moreover, these broadcast schemes may be adapted to satisfying the different receivers' requirements or distributing the classical information, which are important in various quantum applications such as the quantum secret distribution or the quantum network communication. [ABSTRACT FROM AUTHOR]

Immeasurability of a quantum state has important consequence in practical implementation of quantum computers. Our purpose is to analyze the efficiency of the entangled output of Pati-Braunstein deleting machine or Wootters-Zurek quantum copying machine as a quantum channel. Interestingly we find that for special values of the input parameter the state does not violate the Bell's inequality. Moreover, we analyze the performances of the entangled output of Pati-Braunstein deleting after the Wootters-Zurek copying machine. [ABSTRACT FROM AUTHOR]

In this paper, we propose two schemes to remotely split an arbitrary three-qubit state. The χ and a GHZ state are used to construct the quantum channel. One scheme is completed by using the generalized Bell basis measurement of multi-particles. The other scheme is constructed by using the quantum primitives, which are described by the quantum circuit and photon architecture. [ABSTRACT FROM AUTHOR]

This paper is to establish a theoretical framework for faithful and deterministic remote state preparation, which is related to the classical Hurwitz theorem. And then based on the new theory various schemes with different characteristics are presented. Moreover, the permutation group and the partially quantum resources have also discussed for faithful schemes. [ABSTRACT FROM AUTHOR]

Motivated by some previous joint remote preparation schemes, we first propose some quantum circuits and photon circuits that two senders jointly prepare an arbitrary one-qubit state to a remote receiver via GHZ state. Then, by constructing KAK decomposition of some transformation in SO(4), one quantum circuit is constructed for jointly preparing an arbitrary two-qubit state to the remote receiver. Furthermore, some deterministic schemes of jointly preparing one-qubit and two-qubit states are presented. Besides, the proposed schemes are extended to multi-sender and the partially entangled quantum resources. [ABSTRACT FROM AUTHOR]

Various results of the no-cloning theorem, no-deleting theorem and no-superposing theorem in quantum mechanics have been proved using the superposition principle and the linearity of quantum operations. In this paper, we investigate general transformations forbidden by quantum mechanics in order to unify these theorems. First, we prove that any useful information cannot be created from an unknown pure state which is randomly chosen from a Hilbert space according to the Harr measure. And then, we propose a unified no-go theorem based on a generalized no-superposing result. The new theorem includes the no-cloning theorem, no-anticloning theorem, no-partial-erasure theorem, no-splitting theorem, no-superposing theorem or no-encoding theorem as a special case. Moreover, it implies various new results. Third, we extend the new theorem into another form that includes the no-deleting theorem as a special case. [ABSTRACT FROM AUTHOR]