<p>This article investigates thermal entanglement and quantum teleportation in a bipartite system composed of two spin-<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="11128_2025_4668_Article_IEq1.gif" Format="GIF" Height="22" Rendition="HTML" Resolution="72" Type="Linedraw" Width="8" /> </InlineMediaObject> <EquationSource Format="TEX">\(\frac{1}{2}\)</EquationSource> <EquationSource Format="MATHML"><math> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </math></EquationSource> </InlineEquation> qubits, exposed to an external magnetic field along the <i>Z</i>-axis, within the framework of the squeezed spin model. We employ concurrence to quantify both the thermal entanglement in our system and the entanglement of the replicated output state in a quantum teleportation protocol through this system. Thus, we adopt fidelity to evaluate the quality of teleportation. It is shown that at the system’s ground state, a pure state favors maximal entanglement, while a mixed state leads to an absence of entanglement regardless of the magnetic field. At very low temperatures, increasing the magnetic field induces transitions from the entangled state to a separable state, but this transition is modulated by the intensity of interactions in the <i>XY</i>-plane. The intensities of interactions along the X- and Y-axes are studied to understand their effect on the system’s entanglement. Two spin squeezing mechanisms, one-axis twisting and two-axis counter twisting, are compared, revealing that two-axis counter twisting offers better entanglement. Finally, we explore quantum teleportation through squeezed spin states, demonstrating its feasibility with high fidelity at high temperatures and without a magnetic field, provided that the intensities of interactions in the <i>XY</i>-plane are negligible. By increasing the intensities <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="11128_2025_4668_Article_IEq2.gif" Format="GIF" Height="12" Rendition="HTML" Resolution="72" Type="Linedraw" Width="15" /> </InlineMediaObject> <EquationSource Format="TEX">\(\mu \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>μ</mi> </math></EquationSource> </InlineEquation> and <InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="11128_2025_4668_Article_IEq3.gif" Format="GIF" Height="12" Rendition="HTML" Resolution="72" Type="Linedraw" Width="15" /> </InlineMediaObject> <EquationSource Format="TEX">\(\chi \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>χ</mi> </math></EquationSource> </InlineEquation>, fidelity improves. Intriguingly, our analysis suggests that quantum teleportation, with increased fidelity, is achievable only with the one-axis twisting spin squeezing mechanism, remaining out of reach for two-axis counter twisting.</p>

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Quantum teleportation via thermal entanglement in squeezed spin states

  • Abdelghani El Houri,
  • Ayyoub El Mouatasim,
  • Aziz Khribach,
  • Brahim Adnane,
  • Younes Moqine,
  • Rachid Houça,
  • Abdellatif Kamal,
  • Abdelhadi Belouad

摘要

This article investigates thermal entanglement and quantum teleportation in a bipartite system composed of two spin- \(\frac{1}{2}\) 1 2 qubits, exposed to an external magnetic field along the Z-axis, within the framework of the squeezed spin model. We employ concurrence to quantify both the thermal entanglement in our system and the entanglement of the replicated output state in a quantum teleportation protocol through this system. Thus, we adopt fidelity to evaluate the quality of teleportation. It is shown that at the system’s ground state, a pure state favors maximal entanglement, while a mixed state leads to an absence of entanglement regardless of the magnetic field. At very low temperatures, increasing the magnetic field induces transitions from the entangled state to a separable state, but this transition is modulated by the intensity of interactions in the XY-plane. The intensities of interactions along the X- and Y-axes are studied to understand their effect on the system’s entanglement. Two spin squeezing mechanisms, one-axis twisting and two-axis counter twisting, are compared, revealing that two-axis counter twisting offers better entanglement. Finally, we explore quantum teleportation through squeezed spin states, demonstrating its feasibility with high fidelity at high temperatures and without a magnetic field, provided that the intensities of interactions in the XY-plane are negligible. By increasing the intensities \(\mu \) μ and \(\chi \) χ , fidelity improves. Intriguingly, our analysis suggests that quantum teleportation, with increased fidelity, is achievable only with the one-axis twisting spin squeezing mechanism, remaining out of reach for two-axis counter twisting.