The topics of the paper are: a) Some anti-linear maps governing EPR tasks if no reference bases are distinguished. b) Imperfect teleportation and the composition rule. The ancilla is supposed pure but otherwise arbitrary. c) Quantum telportation with distributed measurements. d) Remarks on EPR with a mixed state, triggered by a Lueders measurement.
Stimulated Raman adiabatic passage is a well-known technique for quantum population transfer due to its robustness again various sources of noises. Here we consider quantum population transfer from one spin to another via an intermediate spin which subjects to dephasing noise. We obtain an analytic expression for the transfer efficiency under a specific driving protocol, showing that dephasing could reduce the transfer efficiency, but the effect of dephasing could also be suppressed with a stronger laser coupling or a longer laser duration. We also consider another commonly used driving protoc…
Possible realization of entanglement, logical gates and quantum information transfer with superconducting-quantum-interference-device qubits in cavity QED
Quantum networks consist of quantum nodes that are linked by entanglement and quantum information can be transferred from one node to another. Operations can be applied to qubits of local nodes coordinated by classical communication to manipulate quantum states and readout/measurement will be employed to obtain results. Here, we use quantum circuits to simulate quantum state transfer between two nodes connected in a linear geometry through other nodes. We explore the interplay between gate and readout errors on the performance of state transfer. We find that the nominal success probability is …
We first consider quantum communication protocols between a sender Alice and a receiver Bob, which transfer Alice's quantum information to Bob by means of non-local resources, such as classical communication, quantum communication, and entanglement. In these protocols, we assume that Alice and Bob may have quantum side information, not transferred. In this work, these protocols are called the state transfer with quantum side information. We determine the optimal costs for non-local resources in the protocols, and study what the effects of the use of quantum side information are. Our results ca…
In Phys. Rev. A 74, 030303 (2006), Yung showed that for a one-dimensional spin chain of length $N$ and maximum coupling strength $J_{\max}$, the time $t_0$ for a quantum state to transfer from one end of the chain to another is bounded by $J_{\max} t_0\geqπN/4$ (even $N$) and $J_{\max} t_0\geqπ\sqrt{N^2-1}/4$ (odd $N$). The proof for even $N$ was elegant, but the proof for odd $N$ was less so. This note provides a proof for the odd $N$ case that is simpler, and more in keeping with the proof for the even case.
In many quantum information processing applications, it is important to be able to transfer a quantum state from one location to another - even within a local device. Typical approaches to implement the quantum state transfer rely on unitary evolutions or measurement feedforward operations. However, these existing schemes require accurate pulse operations and/or precise timing controls. Here, we propose a one-way transfer of the quantum state with near unit efficiency using dissipation from a tailored environment. After preparing an initial state, the transfer can be implemented without extern…
Cross-Problem Parameter Transfer in Quantum Approximate Optimization Algorithm: A Machine Learning Approach
Information Sciences University of Delaware Newark, Delaware（信息科学大学德雷克塞尔大学新阿姆斯特朗分校）；Engineering University of Delaware Newark, Delaware（工程大学德雷克塞尔大学新阿姆斯特朗分校）；Astronomy University of Delaware Newark, Delaware（天文学大学德雷克塞尔大学新阿姆斯特朗分校）
We present a systematic analysis and classification of several models of quantum batteries involving different combinations of two level systems and quantum harmonic oscillators. In particular, we study energy transfer processes from a given quantum system, termed charger, to another one, i.e. the proper battery. In this setting, we analyze different figures of merit, including the charging time, the maximum energy transfer, and the average charging power. The role of coupling Hamiltonians which do not preserve the number of local excitations in the charger-battery system is clarified by prope…
