Efficient collection of single photons emitted from a trapped ion into a single-mode fiber for scalable quantum-information processing

Kim, Tae Hyun; Maunz, Peter; Kim, Jungsang

doi:10.1103/physreva.84.063423

Cited by 42 publications

(41 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The collection efficiency of the photon from the ion (enhanced by adequate cavity QED effect [35,36]), wavelength conversion efficiency, and coupling of the resulting photons into the propagating media (fiber) should all be maximized to 90% levels, which remains an experimental challenge.…”

Section: Measurement Outcomesmentioning

confidence: 99%

Ultrafast and Fault-Tolerant Quantum Communication across Long Distances

et al. 2014

Self Cite

View full text Add to dashboard Cite

Quantum repeaters (QRs) provide a way of enabling long distance quantum communication by establishing entangled qubits between remote locations. In this Letter, we investigate a new approach to QRs in which quantum information can be faithfully transmitted via a noisy channel without the use of long distance teleportation, thus eliminating the need to establish remote entangled links. Our approach makes use of small encoding blocks to fault-tolerantly correct both operational and photon loss errors. We describe a way to optimize the resource requirement for these QRs with the aim of the generation of a secure key. Numerical calculations indicate that the number of quantum memory bits at each repeater station required for the generation of one secure key has favorable poly-logarithmic scaling with the distance across which the communication is desired.PACS numbers: 03.67. Dd, 03.67.Hk, 03.67.Pp. Quantum communication across long distances (10 3 -10 4 km) can significantly extend the applications of quantum information protocols such as quantum cryptography [1] and quantum secret sharing [2, 3] which can be used for the creation of a secure quantum internet [4]. Quantum communication can be carried out by first establishing a remote entangled pair between the sender and the receiver and using teleportation to transmit information faithfully. However, there are two main challenges that have to be overcome. First, fiber attenuation during transmission leads to an exponential decrease in entangled pair generation rate. Second, several operational errors such as channel errors, gate errors, measurement errors and quantum memory errors severely degrade the quality of entanglement used for secure key generation. In addition, quantum states cannot be amplified or duplicated deterministically in contrast to classical information [5]. Establishing quantum repeater (QR) stations based on entanglement distribution is the only currently known approach to long-distance quantum communication using conventional optical fibers without exponential penalty in time and resources.A number of schemes have been proposed for long distance quantum communication using , most of which could be broadly classified into three classes. The first class of QRs [6][7][8][9] reduces the exponential scaling of fiber loss to polynomial scaling by introducing intermediate QR nodes. However, this scheme for long distance quantum communication is relatively slow [13], even after optimization [14], limited by the time associated with two-way classical communication between remote stations required for the entanglement purification process needed to correct operational errors [15]. In contrast, the second class of QRs introduce quantum encoding and classical error correction to replace the entanglement purification with classical error correction, handling all operational errors [10,16]. As a consequence, the entanglement generation rate further improves from 1/O(poly(L tot )) to 1/O(poly(log(L tot ))) where L tot is the total distance of communicat...

show abstract

Section: Measurement Outcomesmentioning

confidence: 99%

Ultrafast and Fault-Tolerant Quantum Communication across Long Distances

et al. 2014

Self Cite

View full text Add to dashboard Cite

show abstract

“…With high numerical-aperture collection optics, 10% of the emitted photons can be collected, 51 and more could be extracted through an optical cavity 77,78 integrated with the ion trap. 79 Highly efficient photonic Bell-state detectors with near-ideal mode-matching can be realised in fibre or waveguide beamsplitters 80 and near-unit efficiency photon detectors. 81,82 Taken together, these advances may allow the linking of two ELUs to approach the speed of local Coulomb-based gates (~10 kHz).…”

Section: Integration Technologies For Trapped Ion Quantum Computersmentioning

confidence: 99%

Co-designing a scalable quantum computer with trapped atomic ions

2016

Self Cite

View full text Add to dashboard Cite

The first generation of quantum computers are on the horizon, fabricated from quantum hardware platforms that may soon be able to tackle certain tasks that cannot be performed or modelled with conventional computers. These quantum devices will not likely be universal or fully programmable, but special-purpose processors whose hardware will be tightly co-designed with particular target applications. Trapped atomic ions are a leading platform for first-generation quantum computers, but they are also fundamentally scalable to more powerful general purpose devices in future generations. This is because trapped ion qubits are atomic clock standards that can be made identical to a part in 10 15 , and their quantum circuit connectivity can be reconfigured through the use of external fields, without modifying the arrangement or architecture of the qubits themselves. In this forwardlooking overview, we show how a modular quantum computer with thousands or more qubits can be engineered from ion crystals, and how the linkage between ion trap qubits might be tailored to a variety of applications and quantum-computing protocols. Quantum information processors have the potential to perform computational tasks that are difficult or impossible using conventional modes of computing. 1-3 In a radical departure from classical information, the qubits of a quantum computer can simultaneously store bit values 0 and 1, and when measured they probabilistically assume definite states. Many interacting qubits, isolated from their environment, can represent huge amounts of information: there are exponentially many binary numbers that can co-exist, with entangled qubit correlations that can behave as invisible wires between the qubits. Even in the face of Moore's Law, or the doubling in conventional computer power every year or two, the complexity of massively entangled quantum states of just a few hundred qubits can easily eclipse the capacity of classical information processing. 4 There are but a few known applications that exploit this quantum advantage, such as Shor's factoring algorithm, 5 and future quantum information processors will likely be applied to special-purpose applications. On the other hand, a quantum computer has not yet been built; therefore, new quantum applications and algorithms will likely follow from the evolution and capability of quantum hardware.In the 20 years since the advent of Shor's algorithm 5 and the discovery of quantum error correction, 6-8 there has been remarkable progress in demonstrations of entangling quantum gates on o10 qubits in certain physical systems. Current efforts aim to scale to hundreds, thousands or even millions of interacting qubits. Unlike the classical scaling of bits and logic gates, however, large quantum systems are not comparable to the behaviour of just a few qubits. Just because 2 or 4 qubits can be completely controlled with negligible errors does not mean that this system can readily scale to 4100 qubits.In the last few years, two particular quantum hardware platforms have e...

show abstract

“…As a solution, dielectric mirrors are either placed far away from the trap [6][7][8][9][10] or the dielectric components are well shielded. 16,25,26,57,58 Therefore, when integrating a FFPC into an ion trap, the following restrictions should be respected: the ion-trap potential should be as deep as possible, and the trap geometry should be such that it shields the ion from any charges on the fibers. Furthermore, exposure of the fibers to UV light should be minimized in order to keep them from accumulating charges.…”

Section: A Experimental Design Considerationsmentioning

confidence: 99%

Integrated fiber-mirror ion trap for strong ion-cavity coupling

Brandstätter

McClung

Schüppert

et al. 2013

Review of Scientific Instruments

View full text Add to dashboard Cite

We present and characterize fiber mirrors and a miniaturized ion-trap design developed to integrate a fiber-based Fabry-Perot cavity (FFPC) with a linear Paul trap for use in cavity-QED experiments with trapped ions. Our fiber-mirror fabrication process not only enables the construction of FFPCs with small mode volumes, but also allows us to minimize the influence of the dielectric fiber mirrors on the trapped-ion pseudopotential. We discuss the effect of clipping losses for long FFPCs and the effect of angular and lateral displacements on the coupling efficiencies between cavity and fiber. Optical profilometry allows us to determine the radii of curvature and ellipticities of the fiber mirrors. From finesse measurements, we infer a single-atom cooperativity of up to 12 for FFPCs longer than 200 μm in length; comparison to cavities constructed with reference substrate mirrors produced in the same coating run indicates that our FFPCs have similar scattering losses. We characterize the birefringence of our fiber mirrors, finding that careful fiber-mirror selection enables us to construct FFPCs with degenerate polarization modes. As FFPCs are novel devices, we describe procedures developed for handling, aligning, and cleaning them. We discuss experiments to anneal fiber mirrors and explore the influence of the atmosphere under which annealing occurs on coating losses, finding that annealing under vacuum increases the losses for our reference substrate mirrors. X-ray photoelectron spectroscopy measurements indicate that these losses may be attributable to oxygen depletion in the mirror coating. Special design considerations enable us to introduce a FFPC into a trapped ion setup. Our unique linear Paul trap design provides clearance for such a cavity and is miniaturized to shield trapped ions from the dielectric fiber mirrors. We numerically calculate the trap potential in the absence of fibers. In the experiment additional electrodes can be used to compensate distortions of the potential due to the fibers. Home-built fiber feedthroughs connect the FFPC to external optics, and an integrated nanopositioning system affords the possibility of retracting or realigning the cavity without breaking vacuum.

show abstract

Efficient collection of single photons emitted from a trapped ion into a single-mode fiber for scalable quantum-information processing

Cited by 42 publications

References 50 publications

Ultrafast and Fault-Tolerant Quantum Communication across Long Distances

Ultrafast and Fault-Tolerant Quantum Communication across Long Distances

Co-designing a scalable quantum computer with trapped atomic ions

Integrated fiber-mirror ion trap for strong ion-cavity coupling

Contact Info

Product

Resources

About