Constructions of Unextendible Maximally Entangled Bases in \(\mathbb {C}^{d}\otimes \mathbb {C}^{d^{\prime}}\)

Abstract: We study unextendible maximally entangled bases (UMEBs) in (\mathbb {C}^{d}\otimes \mathbb {C}^{d^{\prime}}) ($d<d'$). An operational method to construct UMEBs containing $d(d^{\prime}-1)$ maximally entangled vectors is established, and two UMEBs in (\mathbb {C}^{5}\otimes \mathbb {C}^{6}) and (\mathbb {C}^{5}\otimes \mathbb {C}^{12}) are given as examples. Furthermore, a systematic way of constructing UMEBs containing $d(d^{\prime}-r)$ maximally entangled vectors in (\mathbb {C}^{d}\otimes \mathbb {C}^{d^{\prime}}) is presented for $r=1,2,\cdots, d-1$. Correspondingly, two UMEBs in (\mathbb {C}^{3}\otimes \mathbb {C}^{10}) are obtained.