The spin-1/2 Ising-Heisenberg trimerized chain in a magnetic field is revisited with the aim to explore the quantum entanglement and non-locality within the exactly solved spin system, which exhibits in a low-temperature magnetization curve two intermediate plateaux at zero and one-third of the saturation magnetization. The groundstate phase diagram involves two quantum (antiferromagnetic, ferrimagnetic I) and two classical (ferrimagnetic II, saturated paramagnetic) phases. We have rigorously calculated the concurrence and Bell function in order to quantify the quantum entanglement and non-locality at zero as well as non-zero temperatures. It is demonstrated that the entanglement can be thermally induced also above the classical ground states unlike the quantum nonlocality, which means that the thermal entanglement is indispensable for a violation of the locality principle. IntroductionQuantum entanglement has attracted a great deal of attention since early work by Einstein, Podolsky and Rosen (EPR) questioned sustainability of quantum mechanics through one of its most famous paradoxes [1]. Interestingly, EPR paradox helped a discovery of the quantum non-locality since Bell put forward inequality, which is violated by certain set of entangled states [2]. It is worthwhile to remark, however, that the quantum entanglement and non-locality are distinct albeit closely related features of quantum-mechanical systems [3]. Moreover, it has been evidenced that the quantum entanglement and non-locality are also capable of detecting phase transitions of quantum spin systems [4][5][6].Quantum effects may have striking macroscopic consequences like for instance presence of quantized plateaux in low-temperature magnetization curves. The magnetization plateaux of quantum spin chains should satisfy Oshikawa-Yamanaka-Affleck rule [7]: p(S u − m u ) = Z, where p is the ground-state period, S u and m u is the total spin and total magnetization of elementary unit and Z is an integer number. This rule represents necessary but not sufficient condition for existence of magnetization plateaux and thus, one should verify their actual existence case by case by performing specific calculations.In the present work, we will revisit the spin-1/2 IsingHeisenberg trimerized chain, which exhibits the stepwise magnetization curve with two intermediate plateaux at zero and one-third of the saturation magnetization either of quantum or classical nature [8]. Our main goal is to investigate the quantum entanglement and non-locality of this model at zero as well as non-zero temperatures.

We investigate robustness of probabilistic storage and retrieval device optimized for phase gates to noise. We use noisy input composed of convex combination of unitary channel with either depolarizing or dephasing channel. We find out that the resistance to dephasing noise is higher than to depolarization. Interestingly, for the depolarisation the retrieval reduces the degree of noise. We also examine the possible realizations showing that their performance is different when the noise is present.