We study$k$-uniform states in heterogeneous systems whose local dimensions are not all the same. Based on the connections between mixed orthogonal arrays with certain minimum Hamming distance, irredundant mixed orthogonal arrays and$k$-uniform states, we present two constructions of 2-uniform states in heterogeneous systems. We also construct two families of 3-uniform states in heterogeneous systems, which solves a question posed in [D. Goyenecheet al., Phys. Rev. A94, 012346 (2016)]. We show two methods of generating$(k-1)$-uniform states from$k$-uniform states. Some results on the nonexistence of absolutely maximally entangled states are provided. For the applications, we present an orthogonal basis consisting of$k$-uniform states with the minimum support, and we show that some$k$-uniform bases are locally irreducible. Moreover, we connect$k$-uniform states with quantum information masking.
We studyk-uniform states in heterogeneous systems whose local dimensions are not all the same. Based on the connections between mixed orthogonal arrays with certain minimum Hamming distance, irredundant mixed orthogonal arrays andk-uniform states, we present two constructions of 2-uniform states in heterogeneous systems. We also construct two families of 3-uniform states in heterogeneous systems, which solves a question posed in [D. Goyenecheet al., Phys. Rev. A94, 012346 (2016)]. We show two methods of generating(k−1)-uniform states fromk-uniform states. Some results on the nonexistence of absolutely maximally entangled states are provided. For the applications, we present an orthogonal basis consisting ofk-uniform states with the minimum support, and we show that somek-uniform bases are locally irreducible. Moreover, we connectk-uniform states with quantum information masking.
Constructions of k-uniform states from mixed orthogonal arrays
We study k-uniform states in heterogeneous systems whose local dimensions are mixed. Based on the connections between mixed orthogonal arrays with certain minimum Hamming distance, irredundant mixed orthogonal arrays and k-uniform states, we present two constructions of 2-uniform states in heterogeneous systems. We also construct a family of 3-uniform states in heterogeneous systems, which solves a question posed in [D. Goyeneche et al., Phys. Rev. A 94, 012346 (2016)]. We also show two methods of generating (k−1)-uniform states from k-uniform states. Some new results on the existence and nonexistence of absolutely maximally entangled states are provided. For the applications, we present an orthogonal basis consisting of k-uniform states with minimum support. Moreover, we show that some k-uniform bases can not be distinguished by local operations and classical communications, and this shows quantum nonlocality with entanglement.
A pure quantum state of n parties associated with the Hilbert space $\CC^{d_1}\otimes \CC^{d_2}\otimes\cdots\otimes \CC^{d_n}$ is called k-uniform if all the reductions to k-parties are maximally mixed. The n partite system is called homogenous if the local dimension d1=d2=⋯=dn, while it is called heterogeneous if the local dimension are not all equal. k-uniform sates play an important role in quantum information theory. There are many progress in characterizing and constructing k-uniform states in homogeneous systems. However, the study of entanglement for heterogeneous systems is much more challenging than that for the homogeneous case. There are very few results known for the k-uniform states in heterogeneous systems for k>3. We present two general methods to construct k-uniform states in the heterogeneous systems for general k. The first construction is derived from the error correcting codes by establishing a connection between irredundant mixed orthogonal arrays and error correcting codes. We can produce many new k-uniform states such that the local dimension of each subsystem can be a prime power. The second construction is derived from a matrix H meeting the condition that HA×Aˉ+HAˉ×AT has full rank for any row index set A of size k. These matrix construction can provide more flexible choices for the local dimensions, i.e., the local dimensions can be any integer (not necessarily prime power) subject to some constraints. Our constructions imply that for any positive integer k, one can construct k-uniform states of a heterogeneous system in many different Hilbert spaces.
A pure quantum state of N subsystems with local dimension d is called a k-uniform state if every reduction to k qudits is maximally mixed. Based on a special class of combinatorial design, namely irredundant orthogonal arrays, we show the existence of 2-uniform N-qudit states when $N\ensuremath{\ge}4$ and d is a prime power other than 2. In addition, given any Hadamard matrix of order greater than 4, we demonstrate how it can be used to construct 3-uniform multiqubit states. In fact, we find that there exists some 3-uniform N-qubit when $N\ensuremath{\ge}8$ except case N=9. These give an answer to a question posed by Goyeneche et al. [Phys. Rev. A 90, 022316 (2014)]. Furthermore, starting from a minimal support k-uniform state, we show how to generate an orthogonal basis consisting of k-uniform states. At last, we derive a series of $(k\ensuremath{-}1)$-uniform $(N\ensuremath{-}1)$-qudit states from a single k-uniform N-qudit state. The k-uniform states are good candidates among the multipartite entangled states.
A pure quantum state ofnparties associated with the Hilbert spaceCd1⊗Cd2⊗⋯⊗Cdnis calledk-uniform if all the reductions tok-parties are maximally mixed. Thenpartite system is called homogenous if the local dimensionsd1=d2=⋯=dn, while it is called heterogeneous if the local dimensions are not all equal.k-uniform sates play an important role in quantum information theory. There are much progress in characterizing and constructingk-uniform states in homogeneous systems. However, the study of entanglement for heterogeneous systems is much more challenging than that for the homogeneous case. There are very few results known for thek-uniform states in heterogeneous systems fork>3. We present two general methods to constructk-uniform states in the heterogeneous systems for generalk. The first construction is derived from the error correcting codes by establishing a connection between irredundant mixed orthogonal arrays and error correcting codes. We can produce many newk-uniform states such that the local dimension of each subsystem can be a prime power. The second construction is derived from a matrixHmeeting the condition thatHA×Aˉ+HAˉ×AThas full rank for any row index setAof sizek. These matrix construction can provide more flexible choices for the local dimensions, i.e., the local dimensions can be any integer (not necessarily prime power) subject to some constraints. Our constructions imply that for any positive integerk, one can constructk-uniform states of a heterogeneous system in many different Hilbert spaces.
A pure state of N parties with local dimension d is called a k-uniform state if all the reductions to k parties are maximally mixed. Based on the connections among k-uniform states, orthogonal arrays and linear codes, we give general constructions for k-uniform states. We show that when d≥4k−2 (resp. d≥2k−1) is a prime power, there exists a k-uniform state for any N≥2k (resp. 2k≤N≤d+1). Specially, we give the existence of 4,5-uniform states for almost every N-qudits. Further, we generalize the concept of quantum information masking in bipartite systems given by [Modi \emph{et al.} {Phys. Rev. Lett. \textbf{120}, 230501 (2018)}] to k-uniform quantum information masking in multipartite systems, and we show that k-uniform states and quantum error-correcting codes can be used for k-uniform quantum information masking.
Abstract A pure quantum state of N subsystems, each with d levels, is said to be k-uniform if all of its reductions to k qudits are maximally mixed. Only the uniform states obtained from orthogonal arrays (OAs) are considered throughout this work. The Hamming distances of OAs are specially applied to the theory of quantum information. By using difference schemes and orthogonal partitions, we construct a series of infinite classes of irredundant orthogonal arrays (IrOAs), then answer the open questions of whether there exist 3-uniform states of N qubits and 2-uniform states of N qutrits, and whether 3-uniform states of qudits (d > 2) for high values of N can be explicitly constructed. In fact, we obtain 3-uniform states for an arbitrary number of N ≥ 8 qubits and 2-uniform states of N qutrits for every N ≥ 4. Additionally, we provide explicit constructions of the 3-uniform states of N ≥ 8 qutrits, N = 6 and N ≥ 8 ququarts and ququints, N ≥ 6 qudits having d levels for any prime power d > 6, and N = 8 and N ≥ 12 qudits having d levels for non-prime-power d ≥ 6. Moreover, we describe an explicit construction scheme for the 2-uniform states of qudits having d ≥ 4 levels. The proofs of existence of the 2-uniform states of N ≥ 6 qubits are simplified by using a class of OAs. Two special 3-uniform states are obtained from IrOA(32, 10, 2, 3) and IrOA(32, 11, 2, 3) using the interaction column property of OAs.