Effect of parity-time symmetric operation on quantum dense coding in non-Markovian environments

Abstract In this work, we investigate the effect of a parity-time ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mi class="MJX-tex-calligraphic">PT</mml:mi> </mml:mrow> </mml:mrow> </mml:math> ) symmetric operation on the dynamic behavior of quantum dense coding for a two-qubit system in non-Markovian environments. First, we derive the explicit expressions of quantum dense coding for an exactly solving model consisting of two qubits interacting with an independent structured reservoir. Then, we give two cases, i.e. resonant and off-resonant regimes, to demonstrate the performance of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mi class="MJX-tex-calligraphic">PT</mml:mi> </mml:mrow> </mml:mrow> </mml:math> symmetric operation on quantum dense coding dynamics. By investigation, we find that the capacity of quantum dense coding can be obviously enhanced with the assistance of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mi class="MJX-tex-calligraphic">PT</mml:mi> </mml:mrow> </mml:mrow> </mml:math> symmetric operation in different regimes. In addition, we show that the optimal local <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mi class="MJX-tex-calligraphic">PT</mml:mi> </mml:mrow> </mml:mrow> </mml:math> symmetric operation can completely protect quantum dense coding. The obtained results imply that the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mi class="MJX-tex-calligraphic">PT</mml:mi> </mml:mrow> </mml:mrow> </mml:math> symmetric operation method may have potential applications in quantum decoherence control.