Restoring number conservation in quadratic bosonic Hamiltonians with dualities

Entanglement dualities in supersymmetry

We derive a general relation between the bosonic and fermionic entanglement in the ground states of supersymmetric quadratic Hamiltonians. For this, we construct canonical identifications between bosonic and fermionic subsystems. Our derivation relies on a unified framework to describe both, bosonic and fermionic Gaussian states in terms of so-called linear complex structures $J$. The resulting dualities apply to the full entanglement spectrum between the bosonic and the fermionic systems, such that the von Neumann entropy and arbitrary Renyi entropies can be related. We illustrate our finding…

$\mathbb{Z}_2$ 格点规范理论：费米子规范、嬗变与 Kramers-Wannier 对偶性

$\mathbb{Z}_2$ lattice gauge theories: fermionic gauging, transmutation, and Kramers-Wannier dualities

本文通过插入马约拉纳费米子推广 $\mathbb{Z}_2$ 对称性规范固定，建立玻色子与费米子格点系统的对偶对应，构造马约拉纳稳定子码，并证明与常规 $\mathbb{Z}_2$ 规范理论的酉等价性，为量子计算提供统一框架。

Restoring Heisenberg limit via collective non-Markovian dephasing

In this work an exactly solvable model of N two-level systems interacting with a single bosonic dephasing reservoir is considered to unravel the role played by collective non-Markovian dephasing. We show that phase estimation with entangled states for this model can exceed the standard quantum limit and demonstrate Heisenberg scaling with the number of atoms for an arbitrary temperature. For a certain class of reservoir densities of states decoherence can be suppressed in the limit of large number of atoms and the Heisenberg limit can be restored for arbitrary interrogation times. We identify …

利用可分离关联恢复破缺纠缠

Restoring broken entanglement by separable correlations

我们考虑两个玻色子高斯通道，其热噪声强到足以打破二体纠缠。在这种情况下，我们展示了两个通道之间存在可分离的相关性是如何能够恢复破碎的纠缠。这种重新激活不仅发生在第三方（Charlie）向远程方（Alice和Bob）广播纠缠态的直接分发方案中，而且发生在基于纠缠交换的间接分发配置中。在这两种方案中，远程激活的纠缠量可以足够大，可以通过单向蒸馏协议进行蒸馏。