Qubit-qutrit海森堡混合自旋链系统QMA熵不确定度的量子调控

在qubit-qutrit海森堡混合自旋链模型中研究了量子存储支撑(Quantum memory assisted,QMA)熵不确定度的量子调控.详细分析了混合自旋链模型中的Dzyaloshinskii-Moriya(DM)相互作用、耦合强度和非均匀磁场对QMA熵不确定度的影响,对比分析了混合自旋链模型中系统参数对QMA熵不确定度和被测系统与存储系统的量子纠缠的调控作用.结果表明,通过调控非均匀磁场强度和混合自旋链系统的参数,可以提高被测系统与存储系统的量子纠缠,降低系统QMA熵不确定度及其下限.

Fast population transfer with a superconducting qutrit via non-Hermitian shortcut to adiabaticity

Non-Hermitian dissipation dynamics,capable of turning the conventionally detrimental decoherence effects to useful resources for state engineering,is highly attractive to quantum information processing.In this work,an effective scheme is developed for implementing fast population transfer with a superconducting qutrit via the non-Hermitian shortcut to adiabaticity(STA).We first deal with aΛ-configuration interaction between the qutrit and microwave drivings,in which the dephasing-assisted qubit state inversion requiring an overlarge dephasing rate is constructed non-adiabatically.After introducing a feasible ancillary driving that directly acts upon the qubit states,the target state transfer can be well realized but with an accessible qubit dephasing rate.Moreover,a high fidelity could be numerically obtained in the considered system.The strategy could provide a new route towards the non-Hermitian shortcut operations on superconducting quantum circuits.

Realization of the iSWAP-like gate among the superconducting qutrits

High-dimensional quantum systems, such as qutrits(quantum three-level systems), have multiple accessible energy levels beyond the two-level qubits. Therefore, qutrits can offer a larger state space to improve the efficiency of quantum computation. Here, we demonstrate a high-fidelity iSWAP-like gate operation on a frequency-tunable superconducting qutrits system. The superconducting quantum system consists of two qutrits that are coupled via a resonator with fixed qutrit-resonator coupling strengths. Through designing the frequency pulse profile and optimizing the parameter values,the gate error can be suppressed below 1.5 × 10^(-3). To bear out the feasibility of the proposal, we have conducted our study with experimentally accessible parameters. As the resonator can mediate the interaction between the irrelevant qutrits, the presented approach can also be used to couple multiple qutrits together, providing a good platform for quantum information processing.

Two-qutrit maximally entangled states prepared via adiabatic passage in ion-trapped system

This paper considers a scheme for the preparation of two-qutrit entangled states via adiabatic passage in iontrapped system. In the proposal, the two three-level V-type ions are initially cooled to the ground states and need not be separately addressed. Moreover, only the ionic states act as memory and the system evolves in the dark space during the whole procedure, which makes the system robust against the decoherence and the fluctuation of the laser pulse.

Correlation dynamics of two-parameter qubit-qutrit states under decoherence

We investigate the dynamics of correlations for two-parameter qubit--qutrit states under various local decoherence channels including depalising, phase-flip, bit- and trit-flip, bit- and trit-phase-flip, and depolarizing channels. We find that, under certain conditions, the classical： correlations may not be affected by the noise or decay monotonically. The quantum correlations measured by measurement-induced disturbance （MID） show three types of dynamical behaviors： （i） monotonic ＇decay to zero, （ii） monotOniC decay to a nonzero steady value, （iii） increase from zero and then decrease to zero in a monotonic way. Consequently, we find that, differing from the dynamics of entanglement, the present classical and quantum correlations do not reveal sudden death behavior.

Nonlocal multi-target controlled controlled gate using Greenberger–Horne–Zeilinger channel and qutrit catalysis

We present a scheme for implementing locally a nonlocal N-target controlled–controlled gate with unit probability of success by harnessing two（N＋1）-qubit Greenberger–Horne–Zeilinger（GHZ） states as quantum channel and N qutrits as catalyser. The quantum network that implements this nonlocal（N＋2）-body gate is built entirely of local single-body and two-body gates, and has only（3N＋2） two-body gates. This result suggests that both the computational depth of quantum network and the quantum resources required to perform this nonlocal gate might be significantly reduced. This scheme can be generalized straightforwardly to implement a nonlocal N-target and M-control qubits gate.

Thermal entanglement in two-qutrit spin-1 anisotropic Heisenberg model with inhomogeneous magnetic field

The thermal entanglement of a two-qutrit spin-1 anisotropic Heisenberg XXZ chain in an inhomogeneous magnetic field is studied in detail. The effects of the external magnetic field （B）, a parameter b which controls the inhomogeneity of B, and the bilinear interaction parameters Jx = Jy ≠ Jz on the thermal variation of the negativity are studied in detail. It is found that negativity N decreases when the values of magnetic field, inhomogeneity b and temperature are increasing. In addition, N remains at higher temperatures for higher values of Jz and lower values of B and b.

Robust generation of qutrit entanglement via adiabatic passage of dark states

We propose a scheme for the deterministic generation of qutrit entanglement for two atoms trapped in an optical cavity. Taking advantage of the adiabatic passage, the operation is immune to atomic spontaneous emission as the atomic excited states are never populated; under certain conditions, the probability that the cavity is excited is negligible. We also study the influences of the dissipation due to the atomic spontaneous emission and cavity decay.

Probabilistically implementing nonlocal operations between two distant qutrits

We propose a method to probabilistically implement a nonlocal operation, exp[iζUAUB], between two distant qutrits A and B, where ζ∈ C [0,2π] and UA, UB are local unitary and Hermitian operations for qutrits A and B respectively. The consumptions of resource for one performance of the method are a single non-maximally entangled qutrit state and 1-trit classical communication. For a given ζ, the successful probability of the method depends on the forms of both entanglement resource and Bob＇s partial-measurement basis. We systematically discuss the optimal successful probabilities and their corresponding conditions for three cases： adjustable entanglement resource, adjustable partial-measurement basis, adjustable entanglement resource and partial-measurement basis. It is straightforward to generalize the method for producing nonlocal unitary operations between any two N-level systems.

Quantum discord of two-qutrit system under quantum-jump-based feedback control

This paper studies quantum discord of two qutrits coupled to their own environments independently and coupled to the same environment simultaneously under quantum-jump-based feedback control. Our results show that spontaneous emission, quantum feedback parameters, classical driving, initial state, and detection efficiency all affect the evolution of quantum discord in a two-qutrit system. We find that under the condition of designing proper quantum-jump-based feedback parameters, quantum discord can be protected and prepared. In the case where two qutrits are independently coupled to their own environments, classical driving, spontaneous emission, and low detection efficiency have negative effect on the protection of quantum discord. For different initial states, it is found that the evolution of quantum discord under the control of appropriate parameters is similar. In the case where two qutrits are simultaneously coupled to the same environment,the classical driving plays a positive role in the generation of quantum discord, but spontaneous emission and low detection efficiency have negative impact on the generation of quantum discord. Most importantly, we find that the steady discord depends on feedback parameters, classical driving, and detection efficiency, but not on the initial state.

One-step generation of qutrit entanglement via adiabatic passage in cavity quantum electrodynamics

A scheme is proposed for generating a three-dimensional entangled state for two atoms trapped in a cavity by one step via adiabatic passage. In the scheme, the two atoms are always in ground states and the field mode of the cavity excited is negligible under a certain condition. Therefore, the scheme is very robust against decoherence. Furthermore, it needs neither the exact control of all parameters nor the accurate control of the interaction time. It is shown that qutrit entanglement can be generated with a high fidelity.

Demonstration of quantum permutation parity determine algorithm in a superconducting qutrit

A quantum algorithm provides a new way in solving certain computing problems and usually faster than classical algorithms. Here we report an implementation of a quantum algorithm to determine the parity of permutation in a single three-dimensional（3D） superconducting transmon qutrit system. The experiment shows the capacity to speed up in a qutrit,which can also be extended to a multi-level system for solving high-dimensional permutation parity determination problem.

Reduction of entropy uncertainty for qutrit system under non-Markov noisy environment

We explore the entropy uncertainty for qutrit system under non-Markov noisy environment and discuss the effects of the quantum memory system and the spontaneously generated interference(SGI)on the entropy uncertainty in detail.The results show that,the entropy uncertainty can be reduced by using the methods of quantum memory system and adjusting of SGI.Particularly,the entropy uncertainty can be decreased obviously when both the quantum memory system and the SGI are simultaneously applied.

Effects of colored noise on the dynamics of quantum entanglement of a one-parameter qubit-qutrit system

We analyzed the effect of colored noise on the negativity dynamics of a hybrid system consisting of a qubit-qutrit and not interacting,prepared from the start in an entangled one-parameter state and acting with noise in local and non-local environments.In this pink and brown noise we investigated two different situations:in the first situation,the noise is produced by a bistable oscillator with an unknown exchange rate;however,in the second situation,the noise is generated by a set of bistable oscillators.We found that entanglement decreases with time to zero,and undergoes the phenomenon of sudden death and rebirth.The pink noise is more prone to entanglement than the brown noise and the non-local environment is more prone to entanglement than the local one.When the number of fluctuators is increased,entanglement decays faster and finally,for certain parameters of the initial state,the subsystems are not affected by the noise.

It from Qutrit: Braided Loop Metaheuristic

Cosmologies are developed by physicists and philosophers to explain our experiences of the evolving cosmos. Intelligent deep-learning metaheuristics provide original frameworks for cosmologies which are founded on quantum information. Mathematical standard models of physical cosmology and particle physics formalize an abundance of observations, yet there is no scientific consensus about how these models include our conscious experiences and fundamental philosophies of information. Furthermore, Naturalness in physics is coupled to the related problem of fine-tuning. To address these foundational problems, within the quantum information paradigm, whilst aligning with standard scientific models, I introduce a topological deep-learning cosmology metaheuristic. Braided, 3-coloured, world-strands are proposed to be the fundamental quantum information tracts (ethereal fibre bundles) of our evolving Triuniverse. This Braided Loop Metaheuristic comprises eternally evolving deep-learning feedback loops of superposed, braided, 3-coloured, quantum information world-strands, which process (in 3-level qutrit states) foundational properties coined Algebrus (labelled red), Algorithmus (labelled green) and Geometrus (labelled blue). Braids split from 1→2→3 (in knot representation respectively: closed loop→trefoil knot→Borromean loops) thence combine from 3→2→1 to form eternally evolving deep-learning loops. This cosmology metaheuristic simultaneously incorporates initial Laws of Form;Emergentism (from substrate Mathematics, through Quantum Physics to Life);Consciousness (as a superposed triunity of Implicate Order, Process Philosophy and Aesthetic Relationalism);Reductionism (from Life, through Quantum Physics to Pure Mathematics expressed as Logical Axioms, Laws of Parsimony and Ideal Form);and the Braided Loop Metaheuristic reboots its eternal cycle with the initial Laws of Form. An agent’s personal anthropic Braided Loop Metaheuristic represents one of many-worlds, a meridional loop in a multiverse with horn-torus topology, where Nature’s physical parameters vary equatorially. Fundamental information processing is driven by ψ-Epistemic Drive, the Natural appetite for information selected for advantageous knowledge. The meridional loops are ψ-Epistemic Field lines emanating from an epistemic dipole at the horn-torus core. Equatorial parameter fine-tuning in many-worlds quantum physics and the many-species of Darwinian Life are similar deep-learning optimizations in the Braided Loop Metaheuristic.

Three-Qutrit Topological SWAP Logic Gate for ISK(I=1,S=1,K=1)Spin System

Three Zeeman levels of spin-1 electron or nucleus are called as qutrits in quantum computation. Then, ISK (I = 1, S = 1, K = 1) spin system can be represented as three-qutrit states. Quantum circuits and algorithms consist of quantum logic gates. By using SWAP logic gate, two quantum states are exchanged. Topological quantum computing can be applied in quantum error correction. In this study, first, Yang-Baxter equation is modified for ISK (I = 1, S = 1, K = 1) spin system. Then three-qutrit topological SWAP logic gate is obtained. This SWAP logic gate is applied for three-qutrit states of ISK (I = 1, S = 1, K = 1) spin system. Three-qutrit SWAP logic gate is also applied to the product operators of ISK (I = 1, S = 1, K = 1) spin system. For these two applications, expected exchange results are found.

Realization of Two-Qutrit Quantum Gates with Control Pulses

我们与 bequsi 相互作用在一个由两部组成的 3 水平系统调查 2-qutrit 逻辑门的实现。根据矩阵的 Cartan 分解， 2-qutrit 的单一的矩阵是进一系列可实现的矩阵的产品的 factorized。它等价于在系统，和控制目标上施加某个控制域被控制脉搏的一个序列通常获得。逻辑门被成为第一的 2-qutrit 的实现的一般讨论，然后实现第三交换门，第三的门明确地被讨论，并且控制脉搏的序列和实现这些门的飘移过程被给。

Controlled Teleportation of Multi-qutrit Quantum Information by Swapping Entanglement

我们在场为在一个网络经由许多代理人的控制从一个发送者移植 multi-qutrit 量信息到接收装置的电视的一个计划。代理人的控制参数经由量纠纷交换被获得。在我们的计划，张和人是 QSS 协议[Phys。加快。一 72 (2005 ) 022303 ] 基于钟状态，纠纷交换被概括到一个 qutrit 盒子。我们的计划拥有比工作有更高的代码能力和更好的安全的优点[Commun。Theor。Phys。44 (2005 ) 847 ] 在为 multi-qubit 的控制远距传物上。

Tripartite Arbitrary Two-Qutrit Quantum State Sharing

为安全地分享一个任意的未知 two-qutrit 状态的一个分成三部分的计划被建议，在二个概括 Greenberger Horne Zeilinger (GHZ ) 状态用作连接三个合法聚会的量隧道的地方。量信息(即，任意的未知 two-qutrit 状态) 从发送者，罐头以如此的一个方法被切开，它能被重建由经由合适的单一的操作的任何代理人的确定的联盟者如果两个代理人一起协作。而且，到更多聚会大小写的分成三部分的计划的归纳也被构画出。

Generalized Quantum Two-Qutrit-State Splitting

A three-party scheme for splitting an arbitrary unknown two-qutrit state is proposed,where two non-maximally-entangled three-qutrit states are taken as the quantum channel among three parties.With the sender'shelp,if and only if both receivers collaborate together,they can securely share the quantum state in a probabilisticway by introducing an ancilla qutrit and performing appropriate unitary operations.The relation between the successprobability and coefficients characterizing the quantum channel is revealed.The security of the present scheme is analyzedand confirmed.Moreover,the generalization of the three-party scheme to more-party case is also sketched.