



01624nas a2200193   4500008004100000245009000041210006900131260001500200520100400215100001701219700002401236700001801260700001601278700002301294700002401317700002401341700002801365856003701393       2019                        eng d00aToward convergence of effective field theory simulations on digital quantum computers0 aToward convergence of effective field theory simulations on digi  c04/18/20193 a<p>We report results for simulating an effective field theory to compute the binding energy of the deuteron nucleus using a hybrid algorithm on a trapped-ion quantum computer. Two increasingly complex unitary coupled-cluster ansaetze have been used to compute the binding energy to within a few percent for successively more complex Hamiltonians. By increasing the complexity of the Hamiltonian, allowing more terms in the effective field theory expansion and calculating their expectation values, we present a benchmark for quantum computers based on their ability to scalably calculate the effective field theory with increasing accuracy. Our result of E4=&minus;2.220&plusmn;0.179MeV may be compared with the exact Deuteron ground-state energy &minus;2.224MeV. We also demonstrate an error mitigation technique using Richardson extrapolation on ion traps for the first time. The error mitigation circuit represents a record for deepest quantum circuit on a trapped-ion quantum computer.&nbsp;</p>1 aShehab, Omar1 aLandsman, Kevin, A.1 aNam, Yunseong1 aZhu, Daiwei1 aLinke, Norbert, M.1 aKeesan, Matthew, J.1 aPooser, Raphael, C.1 aMonroe, Christopher, R.  uhttps://arxiv.org/abs/1904.0433801499nas a2200193   4500008004100000245007800041210006900119260001500188520089900203100002401102700001401126700002101140700001601161700002301177700002301200700001701223700002801240856003701268       2019                        eng d00aTwo-qubit entangling gates within arbitrarily long chains of trapped ions0 aTwoqubit entangling gates within arbitrarily long chains of trap  c05/28/20193 a<p>Ion trap systems are a leading platform for large scale quantum computers. Trapped ion qubit crystals are fully-connected and reconfigurable, owing to their long range Coulomb interaction that can be modulated with external optical forces. However, the spectral crowding of collective motional modes could pose a challenge to the control of such interactions for large numbers of qubits. Here, we show that high-fidelity quantum gate operations are still possible with very large trapped ion crystals, simplifying the scaling of ion trap quantum computers. To this end, we present analytical work that determines how parallel entangling gates produce a crosstalk error that falls off as the inverse cube of the distance between the pairs. We also show experimental work demonstrating entangling gates on a fully-connected chain of seventeen 171Yb+ ions with fidelities as high as 97(1)%.</p>1 aLandsman, Kevin, A.1 aWu, Yukai1 aLeung, Pak, Hong1 aZhu, Daiwei1 aLinke, Norbert, M.1 aBrown, Kenneth, R.1 aDuan, Luming1 aMonroe, Christopher, R.  uhttps://arxiv.org/abs/1905.10421