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# '''Ability to initialize the state of qubits to a simple fiducial state.'''<ref name="DiVincenzo-2008">{{Cite journal |last=DiVincenzo |first=David |date=February 1, 2008 |title=The Physical Implementation of Quantum Computation |journal=IBM T.J. Watson Research Center|volume=48 |issue=9–11 |pages=771–783 |doi=10.1002/1521-3978(200009)48:9/11<771::AID-PROP771>3.0.CO;2-E |arxiv=quant-ph/0002077 |bibcode=2000ForPh..48..771D |s2cid=15439711 }}</ref> A fiducial state is one that is easily and consistently replicable and is useful in quantum computing as it may be used to guarantee the initial state of qubits. One simple way to initialize a superconducting qubit is to wait long enough for the qubits to relax to the ground state. Controlling qubit potential with tuning knobs allows faster initialization mechanisms.
# '''Long relevant decoherence times'''<ref name="DiVincenzo-2008" />'''.''' Decoherence of superconducting qubits is affected by multiple factors. Most decoherence is attributed to the quality of the Josephson junction and imperfections in the chip substrate. Due to their mesoscopic scale, superconducting qubits are relatively short lived. Nevertheless, thousands of gate operations have been demonstrated in these many-qubit systems<ref>{{cite journal |last1=Devoret |first1=M. H. |last2=Schoelkopf |first2=R. J. |title=Superconducting Circuits for Quantum Information: An Outlook |journal=Science |date=7 March 2013 |volume=339 |issue=6124 |pages=1169–1174 |doi=10.1126/science.1231930|pmid=23471399 |bibcode=2013Sci...339.1169D |s2cid=10123022 }}</ref>. Recent strategies to improve device coherence include purifying the circuit materials and designing qubits with decreased sensitivity to noise sources <ref name="Nguyen-2019" />.
# '''A “universal” set of quantum gates.'''<ref name="DiVincenzo-2008" /> Superconducting qubits allow arbitrary rotations in the Bloch sphere with pulsed microwave signals, implementing single qubit gates. <math>\sigma_z \sigma_z</math> and <math>\sigma_x \sigma_x</math> couplings are shown for most implementations and for complementing the universal gate set<ref>{{cite journal |last1=Chow |first1=Jerry M. |last2=Gambetta |first2=Jay M. |last3=Córcoles |first3=A. D. |last4=Merkel |first4=Seth T. |last5=Smolin |first5=John A. |last6=Rigetti |first6=Chad |last7=Poletto |first7=S. |last8=Keefe |first8=George A. |last9=Rothwell |first9=Mary B. |last10=Rozen |first10=J. R. |last11=Ketchen |first11=Mark B. |last12=Steffen |first12=M. |title=Universal Quantum Gate Set Approaching Fault-Tolerant Thresholds with Superconducting Qubits |arxiv=1202.5344 |journal=Physical Review Letters |date=9 August 2012 |volume=109 |issue=6 |pages=060501 |doi=10.1103/PhysRevLett.109.060501|pmid=23006254 |bibcode=2012PhRvL.109f0501C |s2cid=39874288 }}</ref><ref>{{cite journal |last1=Niskanen |first1=A. O. |last2=Harrabi |first2=K. |last3=Yoshihara |first3=F. |last4=Nakamura |first4=Y. |last5=Lloyd |first5=S. |last6=Tsai |first6=J. S. |title=Quantum Coherent Tunable Coupling of Superconducting Qubits |journal=Science |date=4 May 2007 |volume=316 |issue=5825 |pages=723–726 |doi=10.1126/science.1141324|pmid=17478714 |bibcode=2007Sci...316..723N |s2cid=43175104 }}</ref><ref name = "Nguyen-2024">{{cite journal |last1=Nguyen |first1=L.B. |last2=Kim |first2=Y. |last3=Hashim |first3=A. |last4=Goss |first4=N.|last5=Marinelli |first5=B.|last6=Bhandari |first6=B.|last7=Das |first7=D.|last8=Naik |first8=R.K.|last9=Kreikebaum |first9=J.M.|last10=Jordan |first10=A.|last11=Santiago |first11=D.I.|last12=Siddiqi |first12=I. |title=Programmable Heisenberg interactions between Floquet qubits
|journal=Nature Physics |date=16 January 2024 |volume=20 |issue=1 |pages=240-246 |doi=10.1038/s41567-023-02326-7 |bibcode=2024NatPh..20..240N |doi-access=free |arxiv=2211.10383}}</ref>. This criterion may also be satisfied by coupling two transmons with a coupling capacitor.<ref name="docs.pennylane.ai" />
# '''Qubit-specific measurement ability.'''<ref name="DiVincenzo-2008" /> In general, single superconducting qubits are used for control or for measurement.
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