Intraparticle entanglement in noisy quantum channels: degradation and revival through amplitude damping

Animesh Sinha Roy¹Namitha CV¹Subroto Mukerjee²Prasanta K Panigrahi³Urbasi Sinha^1*

• ¹Raman Research Institute, Bangalore, India
• ²Indian Institute of Science (IISc), Bangalore, Karnataka, India
• ³Indian Institute of Science Education and Research Kolkata, Kolkata, West Bengal, India

Quantum correlations between two or more different degrees of freedom of the same particle are sometimes referred to as intraparticle entanglement. In this work, we study these intra-particle correlations between two different degrees of freedom under various decoherence channels, viz. amplitude damping, depolarizing and phase damping channels. We mainly focus on the amplitude damping channel for which we obtain an exact analytical expression for the concurrence of an arbitrary initial pure state. In this channel, we observe the unique feature of entanglement arising from a separable initial state. We also show that this channel allows for a revival of entanglement with increasing damping parameter including from a zero value of the concurrence. We also consider the amplitude damping channel for interparticle entanglement and show that it does not display any of the above-mentioned interesting features. Further, for comparable parameters, the decay of entanglement in the interparticle system is much greater than in the intraparticle system, which we also find to be true for the phase damping and depolarizing channels. Thus, intraparticle entanglement subjected to damping is much more robust than interparticle entanglement.