scholarly journals Protocol for generation of high-dimensional entanglement from an array of non-interacting photon emitters

Author(s):  
Thomas Bell ◽  
Jacob F F Bulmer ◽  
Alex Jones ◽  
Stefano Paesani ◽  
Dara McCutcheon ◽  
...  

Abstract Encoding high-dimensional quantum information into single photons can provide a variety of benefits for quantum technologies, such as improved noise resilience. However, the efficient generation of high-dimensional entanglement was thought to be out of reach for current and near-future photonic quantum technologies. We present a protocol for the near-deterministic generation of N-photon, d-dimensional photonic Greenberger-Horne-Zeilinger (GHZ) states using an array of d non-interacting single-photon emitters. We analyse the impact on performance of common sources of error for quantum emitters, such as photon spectral distinguishability and temporal mismatch, and find they are readily correctable with time-resolved detection to yield high fidelity GHZ states of multiple qudits. When applied to a quantum key distribution scenario, our protocol exhibits improved loss tolerance and key rates when increasing the dimensionality beyond binary encodings.

Cryptography ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 24
Author(s):  
Noah Cowper ◽  
Harry Shaw ◽  
David Thayer

The ability to send information securely is a vital aspect of today’s society, and with the developments in quantum computing, new ways to communicate have to be researched. We explored a novel application of quantum key distribution (QKD) and synchronized chaos which was utilized to mask a transmitted message. This communication scheme is not hampered by the ability to send single photons and consequently is not vulnerable to number splitting attacks like other QKD schemes that rely on single photon emission. This was shown by an eavesdropper gaining a maximum amount of information on the key during the first setup and listening to the key reconciliation to gain more information. We proved that there is a maximum amount of information an eavesdropper can gain during the communication, and this is insufficient to decode the message.


2020 ◽  
Vol 18 (06) ◽  
pp. 2050031
Author(s):  
Ali Mehri-Toonabi ◽  
Mahdi Davoudi Darareh ◽  
Shahrooz Janbaz

In this work, we introduce a high-dimensional polarization-phase (PoP)-based quantum key distribution protocol, briefly named PoP[Formula: see text], where [Formula: see text] is the dimension of a hybrid quantum state including polarization and phase degrees of freedom of the same photon, and [Formula: see text] is the number of mutually unbiased bases. We present a detailed description of the PoP[Formula: see text] protocol as a special case, and evaluate its security against various individual and coherent eavesdropping strategies, and in each case, we compare it with the BB84 and the two-dimensional (TD)-PoP protocols. In all the strategies, the error threshold and the effective transmission rate of the PoP[Formula: see text] protocol are far greater than the other two protocols. Unlike most high-dimensional protocols, the simplicity of producing and detecting the qudits and the use of conventional components (such as traditional single-photon sources and quantum channels) are among the features of the PoP[Formula: see text] protocol.


2021 ◽  
Author(s):  
Huan Zhao ◽  
Michael Pettes ◽  
Yu Zheng ◽  
Han Htoon

Abstract Quantum emitters (QEs) in two-dimensional transition metal dichalcogenides (2D TMDCs) have advanced to the forefront of quantum communication and transduction research1 due to their unique potentials in accessing valley pseudo-spin degree of freedom (DOF)2 and facile integration into quantum-photonic, electronic and sensing platforms via the layer-by-layer-assembly approach.3 To date, QEs capable of operating in O-C telecommunication bands have not been demonstrated in TMDCs.4-7 Here we report a deterministic creation of such telecom QEs emitting over the 1080 to 1550 nm wavelength range via coupling of 2D molybdenum ditelluride (MoTe2) to strain inducing nano-pillar arrays.8,9 Our Hanbury Brown and Twiss experiment conducted at 10 K reveals clear photon antibunching with 90% single photon purity. Ultra-long lifetimes, 4-6 orders of magnitude longer than that of the 2D exciton, are also observed. Polarization analysis further reveals that while some QEs display cross-linearly polarized doublets with ~1 meV splitting resulting from the strain induced anisotropic exchange interaction, valley degeneracy is preserved in other QEs. Valley Zeeman splitting as well as restoring of valley symmetry in cross-polarized doublets are observed under 8T magnetic field. In contrast to other telecom QEs,10-12 our QEs which offer the potential to access valley DOF through single photons, could lead to unprecedented advantages in optical fiber-based quantum networks.


Quantum ◽  
2018 ◽  
Vol 2 ◽  
pp. 111 ◽  
Author(s):  
Frédéric Bouchard ◽  
Khabat Heshami ◽  
Duncan England ◽  
Robert Fickler ◽  
Robert W. Boyd ◽  
...  

Quantum key distribution is on the verge of real world applications, where perfectly secure information can be distributed among multiple parties. Several quantum cryptographic protocols have been theoretically proposed and independently realized in different experimental conditions. Here, we develop an experimental platform based on high-dimensional orbital angular momentum states of single photons that enables implementation of multiple quantum key distribution protocols with a single experimental apparatus. Our versatile approach allows us to experimentally survey different classes of quantum key distribution techniques, such as the 1984 Bennett & Brassard (BB84), tomographic protocols including the six-state and the Singapore protocol, and to investigate, for the first time, a recently introduced differential phase shift (Chau15) protocol using twisted photons. This enables us to experimentally compare the performance of these techniques and discuss their benefits and deficiencies in terms of noise tolerance in different dimensions.


Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 916
Author(s):  
Maxim Rakhlin ◽  
Sergey Sorokin ◽  
Dmitrii Kazanov ◽  
Irina Sedova ◽  
Tatiana Shubina ◽  
...  

We report on single photon emitters for the green-yellow spectral range, which comprise a CdSe/ZnSe quantum dot placed inside a semiconductor tapered nanocolumn acting as a multimode nanoantenna. Despite the presence of many optical modes inside, such a nanoantenna is able to collect the quantum dot radiation and ensure its effective output. We demonstrate periodic arrays of such emitters, which are fabricated by focused ion beam etching from a II-VI/III-V heterostructure grown using molecular beam epitaxy. With non-resonant optical pumping, the average count rate of emitted single photons exceeds 5 MHz with the second-order correlation function g(2)(0) = 0.25 at 220 K. Such single photon emitters are promising for secure free space optical communication lines.


Author(s):  
D. B. Horoshko ◽  
S. Ya. Kilin

We consider an unambiguous state discrimination attack on the B92 protocol of quantum key distribution, realized on the basis of polarization encoding of photons produced by a single-photon source. We calculate the secure key rate and the maximal tolerable loss for various overlaps between two signal states employed in this protocol. We make also a comparison with a physically impossible attack of perfect quantum cloning, and show that the unambiguous state discrimination is much more dangerous for the B92 protocol, than this attack, demonstrating thus, that the security of quantum key distribution is not always based on the no-cloning theorem.


2017 ◽  
Vol 381 (16) ◽  
pp. 1393-1397 ◽  
Author(s):  
Yang Wang ◽  
Wan-Su Bao ◽  
Hai-Ze Bao ◽  
Chun Zhou ◽  
Mu-Sheng Jiang ◽  
...  

Author(s):  
Duncan G. Steel

In the digital world, the concepts of on and off or high and low or 0 and 1 are common classical two-state systems. Quantum systems can be similarly configured, as we saw in Chapter 9 with the demonstration of Rabi oscillations. Two-state or few-state systems are so important that a powerful algebra has been developed to study and explore these systems. A similar algebra emerged from the algebra developed for spin ½ particles. While Chapter 10 discussed the spinors and spin matrices and the corresponding Pauli matrices, in this chapter the corresponding commutators are determined for the various atomic operators first introduced in Chapter 15. We then move to the Heisenberg picture including the operators for the vacuum field. The Heisenberg equations of motion are derived following the rules in Chapter 8 when a classical electromagnetic field is present and then in the presence of the quantum vacuum to include the effects of decay. This provides the first means of handling the return of an excited population back to the ground state which is very challenging to deal with in the amplitude picture. This chapter is enormously important because it sets the stage for much more advanced studies in advanced texts that determine the impact of fluctuations of the field and correlations measured from single photon emitters.


2020 ◽  
Vol 9 (5) ◽  
pp. 253-261
Author(s):  
Brendon L. Higgins ◽  
Jean-Philippe Bourgoin ◽  
Thomas Jennewein

AbstractOwing to physical orientations and birefringence effects, practical quantum information protocols utilizing optical polarization need to handle misalignment between preparation and measurement reference frames. For any such capable system, an important question is how many resources – for example, measured single photons – are needed to reliably achieve alignment precision sufficient for the desired quantum protocol. Here, we study the performance of a polarization-frame alignment scheme used in prior laboratory and field quantum key distribution (QKD) experiments by performing Monte Carlo numerical simulations. The scheme utilizes, to the extent possible, the same single-photon-level signals and measurements as for the QKD protocol being supported. Even with detector noise and imperfect sources, our analysis shows that only a small fraction of resources from the overall signal – a few hundred photon detections, in total – are required for good performance, restoring the state to better than 99% of its original quality.


Author(s):  
Sabine Euler ◽  
Erik Fitzke ◽  
Oleg Nikiforov ◽  
Daniel Hofmann ◽  
Till Dolejsky ◽  
...  

AbstractIn our laboratory, we employ two biphoton sources for quantum key distribution. The first is based on cw parametric down-conversion of photons at 404 nm in PPKTP waveguide chips, while the second is based on the pulsed parametric down-conversion of 775 nm photons in PPLN waveguides. The spectral characterization is important for the determination of certain side-channel attacks. A Hong-Ou-Mandel experiment employing the first photon source revealed a complex structure of the common Hong-Ou-Mandel dip. By measuring the spectra of the single photons at 808 nm, we were able to associate these structures to the superposition of different transverse modes of the pump photons in our waveguide chips. The pulsed source was characterized by means of single-photon spectra measured by a sensitive spectrum analyzer as well as dispersion-based measurements. Finally, we also describe Hong-Ou-Mandel experiments using the photons from the second source.


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