<p>We investigate the Quantum Fisher Information (QFI) in a system of two excitonic qubits embedded in coupled semiconductor quantum dots, focusing on its dependence on thermal effects and key system parameters: Förster coupling (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">$\lambda $</EquationSource> <EquationSource Format="MATHML"><math> <mi>λ</mi> </math></EquationSource> </InlineEquation>), electric field (<InlineEquation ID="IEq2"> <EquationSource Format="TEX">$\hbar \Omega $</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>ħ</mi> <mi mathvariant="normal">Ω</mi> </mrow> </math></EquationSource> </InlineEquation>), and exciton–exciton dipole interaction energy (<InlineEquation ID="IEq3"> <EquationSource Format="TEX">$\hbar J_z$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>ħ</mi> <msub> <mi>J</mi> <mi>z</mi> </msub> </mrow> </math></EquationSource> </InlineEquation>). Moreover, we examine the intricate interdependencies among these parameters to provide deeper insights. Our findings reveal a non-monotonic temperature dependence of QFI, peaking at intermediate temperatures and vanishing at higher ones. We identify Förster coupling and exciton–exciton dipole interaction energy as crucial factors in enhancing QFI. Electric fields exhibit a dual effect: weak fields maintain it effectively at lower temperatures, while stronger fields enhance its resilience by prolonging its lifetime at smaller values across higher temperature ranges. We achieve the optimal QFI by balancing these parameters. Thus, a strong <InlineEquation ID="IEq4"> <EquationSource Format="TEX">$\hbar J_z$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>ħ</mi> <msub> <mi>J</mi> <mi>z</mi> </msub> </mrow> </math></EquationSource> </InlineEquation> combined with a minimal <InlineEquation ID="IEq5"> <EquationSource Format="TEX">$\hbar \Omega $</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>ħ</mi> <mi mathvariant="normal">Ω</mi> </mrow> </math></EquationSource> </InlineEquation> maximizes effectively QFI. Moreover, <InlineEquation ID="IEq6"> <EquationSource Format="TEX">$\lambda $</EquationSource> <EquationSource Format="MATHML"><math> <mi>λ</mi> </math></EquationSource> </InlineEquation> plays a key role in amplifying it, especially when <InlineEquation ID="IEq7"> <EquationSource Format="TEX">$\hbar \Omega $</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>ħ</mi> <mi mathvariant="normal">Ω</mi> </mrow> </math></EquationSource> </InlineEquation> is weak or absent, its synergy with strong <InlineEquation ID="IEq8"> <EquationSource Format="TEX">$\hbar \Omega $</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>ħ</mi> <mi mathvariant="normal">Ω</mi> </mrow> </math></EquationSource> </InlineEquation> further boosts this enhancement. These insights contribute to optimizing coupled quantum dots for metrology and sensing applications, offering practical strategies for improving quantum measurement precision.</p>

Variations of quantum Fisher information in excitonic qubits

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发表日期：

2025年11月14日

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Fatima-Zahra Siyouri

摘要

We investigate the Quantum Fisher Information (QFI) in a system of two excitonic qubits embedded in coupled semiconductor quantum dots, focusing on its dependence on thermal effects and key system parameters: Förster coupling ( $\lambda $ $λ$ ), electric field ( $\hbar \Omega $ $ħ Ω$ ), and exciton–exciton dipole interaction energy ( $\hbar J_z$ $ħ J_{z}$ ). Moreover, we examine the intricate interdependencies among these parameters to provide deeper insights. Our findings reveal a non-monotonic temperature dependence of QFI, peaking at intermediate temperatures and vanishing at higher ones. We identify Förster coupling and exciton–exciton dipole interaction energy as crucial factors in enhancing QFI. Electric fields exhibit a dual effect: weak fields maintain it effectively at lower temperatures, while stronger fields enhance its resilience by prolonging its lifetime at smaller values across higher temperature ranges. We achieve the optimal QFI by balancing these parameters. Thus, a strong $\hbar J_z$ $ħ J_{z}$ combined with a minimal $\hbar \Omega $ $ħ Ω$ maximizes effectively QFI. Moreover, $\lambda $ $λ$ plays a key role in amplifying it, especially when $\hbar \Omega $ $ħ Ω$ is weak or absent, its synergy with strong $\hbar \Omega $ $ħ Ω$ further boosts this enhancement. These insights contribute to optimizing coupled quantum dots for metrology and sensing applications, offering practical strategies for improving quantum measurement precision.