1,557 research outputs found
Threshold quantum cryptograph based on Grover's algorithm
Grover's operator in the two-qubit case can transform a basis into its
conjugated basis. A permutation operator can transform a state in the two
conjugated bases into its orthogonal state. These properties are included in a
threshold quantum protocol. The proposed threshold quantum protocol is secure
based the proof that the legitimate participators can only eavesdrop 2 bits of
3 bits operation information on one two-qubit with error probability 3/8. We
propose a scheme to detect the Trojan horse attack without destroying the legal
qubit.Comment: 7 pages, 1 figure
Multilevel leapfrogging initialization for quantum approximate optimization algorithm
The quantum approximate optimization algorithm (QAOA) is a prospective hybrid
quantum-classical algorithm widely used to solve combinatorial optimization
problems. However, the external parameter optimization required in QAOA tends
to consume extensive resources to find the optimal parameters of the
parameterized quantum circuit, which may be the bottleneck of QAOA. To meet
this challenge, we first propose multilevel leapfrogging learning (M-Leap) that
can be extended to quantum reinforcement learning, quantum circuit design, and
other domains. M-Leap incrementally increases the circuit depth during
optimization and predicts the initial parameters at level () based
on the optimized parameters at level , cutting down the optimization rounds.
Then, we propose a multilevel leapfrogging-interpolation strategy (MLI) for
initializing optimizations by combining M-Leap with the interpolation
technique. We benchmark its performance on the Maxcut problem. Compared with
the Interpolation-based strategy (INTERP), MLI cuts down at least half the
number of rounds of optimization for the classical outer learning loop.
Remarkably, the simulation results demonstrate that the running time of MLI is
1/3 of INTERP when MLI gets quasi-optimal solutions. In addition, we present
the greedy-MLI strategy by introducing multi-start, which is an extension of
MLI. The simulation results show that greedy-MLI can get a higher average
performance than the remaining two methods. With their efficiency to find the
quasi-optima in a fraction of costs, our methods may shed light in other
quantum algorithms
Long-Term Follow-Up of the Fellow Eye in Patients Undergoing Surgery on One Eye for Treating Myopic Traction Maculopathy
Objective. To observe the fellow eye in patients undergoing surgery on one eye for treating myopic traction maculopathy. Methods. 99 fellow eyes of consecutive patients who underwent unilateral surgery to treat MTM were retrospectively evaluated. All patients underwent thorough ophthalmologic examinations, including age, gender, duration of follow-up, refraction, axial length, intraocular pressure, lens status, presence/absence of a staphyloma, and best-corrected visual acuity (BCVA). Fundus photographs and SD-OCT images were obtained. When feasible, MP-1 microperimetry was performed to evaluate macular sensitivity and fixation stability. Results. At an average follow-up time of 24.7 months, 7% fellow eyes exhibited partial or complete MTM resolution, 68% stabilized, and 25% exhibited progression of MTM. Of the 38 eyes with “normal” macular structure on initial examination, 11% exhibited disease progression. The difference in progression rates in Groups 2, 3, and 4 was statistically significant. Refraction, axial length, the frequency of a posterior staphyloma, chorioretinal atrophy, initial BCVA, final BCVA, and retinal sensitivity all differed significantly among Groups 1–4. Conclusions. Long axial length, chorioretinal atrophy, a posterior staphyloma, and anterior traction contribute to MTM development. Patients with high myopia and unilateral MTM require regular OCT monitoring of the fellow eye to assess progression to myopic pre-MTM. For cases exhibiting one or more potential risk factors, early surgical intervention may maximize the visual outcomes
Quantum Attacks on Type-1 Generalized Feistel Schemes
Generalized Feistel schemes (GFSs) are extremely important and extensively researched cryptographic schemes. In this paper, we investigate the security of Type-1 GFS in quantum circumstances. On the one hand, in the qCCA setting, we give a new quantum polynomial-time distinguisher on -round Type-1 GFS with branches , which extends the previous results by rounds. This leads to a more efficient analysis of type-1 GFS, that is, the complexity of some previous key-recovery attacks is reduced by a factor of , where is the key length of the internal round function. On the other hand, for CAST-256, which is a certain block cipher based on Type-1 GFS, we give a 17-round quantum distinguisher in the qCPA setting. Based on this, we construct an -round quantum key-recovery attack with complexity
Quantum Attacks on Beyond-Birthday-Bound MACs
In this paper, we investigate the security of several recent MAC constructions with provable security beyond the birthday bound (called BBB MACs) in the quantum setting. On the one hand, we give periodic functions corresponding to targeted MACs (including PMACX, PMAC with parity, HPxHP, and HPxNP), and we can recover secret states using Simon algorithm, leading to forgery attacks with complexity . This implies our results realize an exponential speedup compared with the classical algorithm. Note that our attacks can even break some optimally secure MACs, such as mPMAC+-f, mPMAC+-p1, mPMAC+-p2, mLightMAC+-f, etc. On the other hand, we construct new hidden periodic functions based on SUM-ECBC-like MACs: SUM-ECBC, PolyMAC, GCM-SIV2, and 2K-ECBCPlus, where periods reveal the information of the secret key. Then, by applying Grover-meets-Simon algorithm to specially constructed functions, we can recover full keys with or quantum queries, where is the message block size and is the length of the key. Considering the previous best quantum attack, our key-recovery attacks achieve a quadratic speedup
Local Anesthesia at ST36 to Reveal Responding Brain Areas to deqi
Background. Development of non-deqi control is still a challenge. This study aims to set up a potential approach to non-deqi control by using lidocaine anesthesia at ST36. Methods. Forty healthy volunteers were recruited and they received two fMRI scans. One was accompanied with manual acupuncture at ST36 (DQ group), and another was associated with both local anesthesia and manual acupuncture at the same acupoint (LA group). Results. Comparing to DQ group, more than 90 percent deqi sensations were reduced by local anesthesia in LA group. The mainly activated regions in DQ group were bilateral IFG, S1, primary motor cortex, IPL, thalamus, insula, claustrum, cingulate gyrus, putamen, superior temporal gyrus, and cerebellum. Surprisingly only cerebellum showed significant activation in LA group. Compared to the two groups, bilateral S1, insula, ipsilateral IFG, IPL, claustrum, and contralateral ACC were remarkably activated. Conclusions. Local anesthesia at ST36 is able to block most of the deqi feelings and inhibit brain responses to deqi, which would be developed into a potential approach for non-deqi control. Bilateral S1, insula, ipsilateral IFG, IPL, claustrum, and contralateral ACC might be the key brain regions responding to deqi
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