Recovering entanglement by local operations

D’Arrigo, A.; Franco, Rosario Lo; Benenti, Giuliano; Paladino, E.; Falci, G.

doi:10.1016/j.aop.2014.07.021

Cited by 119 publications

(105 citation statements)

References 57 publications

Supporting

Mentioning

104

Contrasting

Order By: Relevance

“…In these systems entanglement revivals may also be induced by applying local pulses to the qubits [13,14,34].…”

Section: Discussionmentioning

confidence: 99%

“…The hidden entanglement [14] of the ensemble A is defined as the difference between the average entanglement of Eq. (10) and the entanglement of the corresponding density operator ρ(t) = i p i |ϕ i (t) ϕ i (t)|:…”

Section: Dephasing Under a "Static" Rt Processmentioning

confidence: 99%

“…In a recent work [14], we have proposed to solve the apparent paradox by introducing the concept of hidden entanglement (HE), which measures the amount of entanglement that may be recovered without the help of any nonlocal operation. The definition of HE is based on the quantum trajectory description of the system dynamics, that allows to point out the presence of entanglement in the system even if the density operator formalism does not reveal it: this entanglement is thus not accessible (hidden) due to the lack of classical information [14].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Hidden entanglement in the presence of random telegraph dephasing noise

et al. 2013

View full text Add to dashboard Cite

Abstract. Entanglement dynamics of two noninteracting qubits, locally affected by random telegraph noise at pure dephasing, exhibits revivals. These revivals are not due to the action of any nonlocal operation, thus their occurrence may appear paradoxical since entanglement is by definition a nonlocal resource. We show that a simple explanation of this phenomenon may be provided by using the (recently introduced) concept of hidden entanglement, which signals the presence of entanglement that may be recovered with the only help of local operations.

show abstract

“…In these systems entanglement revivals may also be induced by applying local pulses to the qubits [13,14,34].…”

Section: Discussionmentioning

confidence: 99%

Section: Dephasing Under a "Static" Rt Processmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hidden entanglement in the presence of random telegraph dephasing noise

et al. 2013

View full text Add to dashboard Cite

show abstract

“…Recently, the lifetime of an entangled state of a superconducting flux qubit coupled to a microscopic two-level fluctuator has been enhanced by DD techniques 52 . Entanglement preservation between independent qubits (storage) from local pure dephasing random-telegraph and 1/f noise by dynamical decoupling has been predicted 53,54 and demonstrated in an all-optical experiment 55 .…”

Section: Introductionmentioning

confidence: 99%

High-fidelity two-qubit gates via dynamical decoupling of local1/fnoise at the optimal point

D’Arrigo¹,

Falci²,

Paladino³

2016

Phys. Rev. A

Self Cite

View full text Add to dashboard Cite

We investigate the possibility to achieve high-fidelity universal two-qubit gates by supplementing optimal tuning of individual qubits with dynamical decoupling (DD) of local 1/f noise. We consider simultaneous local pulse sequences applied during the gate operation and compare the efficiencies of periodic, Carr-Purcell and Uhrig DD with hard π-pulses along two directions (π z/y pulses). We present analytical perturbative results (Magnus expansion) in the quasi-static noise approximation combined with numerical simulations for realistic 1/f noise spectra. The gate efficiency is studied as a function of the gate duration, of the number n of pulses, and of the high-frequency roll-off. We find that the gate error is non-monotonic in n, decreasing as n −α in the asymptotic limit, α ≥ 2 depending on the DD sequence. In this limit πz-Urhig is the most efficient scheme for quasi-static 1/f noise, but it is highly sensitive to the soft UV-cutoff. For small number of pulses, πz control yields anti-Zeno behavior, whereas πy pulses minimize the error for a finite n. For the current noise figures in superconducting qubits, two-qubit gate errors ∼ 10 −6 , meeting the requirements for fault-tolerant quantum computation, can be achieved. The Carr-Purcell-Meiboom-Gill sequence is the most efficient procedure, stable for 1/f noise with UV-cutoff up to gigahertz.

show abstract

“…In the theory of open quantum systems, the non-Markovian dynamics is one of main concerns being linked to the preservation of quantum memory stored in a quantum system [1,4,5]. It arises in many realistic situations [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], and also proves useful in quantum information processing such as quantum state engineering, quantum channel capacity and quantum control [4,[24][25][26][27][28]. The degree of a non-Markovian evolution, the socalled non-Markovianity, can be quantified by different measures based on dynamical features of the system capable to grasp the memory effects of the environment on the system evolution [28][29][30][31][32][33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Harnessing non-Markovian quantum memory by environmental coupling

2015

View full text Add to dashboard Cite

Controlling the non-Markovian dynamics of open quantum systems is essential in quantum information technology since it plays a crucial role in preserving quantum memory. Albeit in many realistic scenarios the quantum system can simultaneously interact with composite environments, this condition remains little understood, particularly regarding the effect of the coupling between environmental parts. We analyze the non-Markovian behavior of a qubit interacting at the same time with two coupled single-mode cavities which in turn dissipate into memoryless or memory-keeping reservoirs. We show that increasing the control parameter, that is the two-mode coupling, allows for triggering and enhancing a non-Markovian dynamics for the qubit starting from a Markovian one in absence of coupling. Surprisingly, if the qubit dynamics is non-Markovian for zero control parameter, increasing the latter enables multiple transitions from non-Markovian to Markovian regimes. These results hold independently on the nature of the reservoirs. This work highlights that suitably engineering the coupling between parts of a compound environment can efficiently harness the quantum memory, stored in a qubit, based on non-Markovianity.

show abstract

Recovering entanglement by local operations

Cited by 119 publications

References 57 publications

Hidden entanglement in the presence of random telegraph dephasing noise

Hidden entanglement in the presence of random telegraph dephasing noise

High-fidelity two-qubit gates via dynamical decoupling of local1/fnoise at the optimal point

Harnessing non-Markovian quantum memory by environmental coupling

Contact Info

Product

Resources

About